Chiral Lewis Acids in Organic Synthesis E-Book
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- Herausgeber: Wiley-VCH Verlag GmbH & Co. KGaA
- Kategorie: Wissenschaft und neue Technologien
- Sprache: Englisch
A complete overview covering the application of metal-based chiral Lewis acids from all parts of the periodic table, the Author emphasizes the most recent contributions to the field as well as prominent direction of development.
The book discusses the design of chiral complexes as well as a wide spectrum of reactions promoted by various chiral Lewis acids, including water-compatible acids as well as the most important applications in the chemical and pharmaceutical industries.
A must-have for catalytic and organic chemists working in the field, both in academia and industry, as well as pharmaceutical and medicinal chemists.
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Seitenzahl: 612
Veröffentlichungsjahr: 2017
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Table of Contents
Cover
Title Page
Copyright
List of Contributors
Preface
Chapter 1: Alkaline-Earth Metal-Based Chiral Lewis Acids
1.1 Introduction
1.2 General Properties of Alkaline Earth Metal Compounds
1.3 Applications in Asymmetric Synthesis
References
Chapter 2: Titanium-Based Chiral Lewis Acids
2.1 Introduction
2.2 Asymmetric Addition of Carbon Nucleophiles to Carbonyl Compounds
2.3 Asymmetric Cyanide Addition Reaction
2.4 Asymmetric Epoxidation
2.5 Asymmetric Darzens Reaction
2.6 Asymmetric Ring-opening Reaction
2.7 Asymmetric Sulfoxidation Reaction
2.8 Asymmetric Hetero-Diels–Alder (HDA) Reaction
2.9 Asymmetric Fluorination of 1,3-Dicarbonyl Compounds
2.10 Asymmetric Sulfenylation of 1,3-Dicarbonyl Compounds
2.11 Asymmetric Formal Intramolecular C(sp2)–H Insertion of
N-
Aryl α-Diazoamides
2.12 Asymmetric Reduction of Ketones
2.13 Asymmetric Hydroalkoxylation of Nonactivated Alkenes
2.14 Asymmetric Titanium(III)-Catalyzed Reductive Coupling Reactions
2.15 Asymmetric 1,3-Dipolar Cycloaddition of Nitrone and Unsaturated Aldehyde
2.16 Asymmetric Friedel–Crafts Alkylation Reaction
2.17 Conclusions
Acknowledgments
References
Chapter 3: Iron-based Chiral Lewis Acids
3.1 Introduction
3.2 Chiral Iron Porphyrins
3.3 Chiral Iron Bipyridines
3.4 Chiral Salen–Salan Lewis Acid Catalysts
3.5 Bis(oxazoline) Lewis Acid Catalysts
3.6 Pyridine Bis(oxazoline) Lewis Acid Catalysts
3.7 Diamine-derived Lewis Acid Catalysts
3.8 Diphosphine-derived Lewis Acid Catalysts
3.9 Binaphthyl-derived Lewis Acid Catalysts
3.10 Other Iron Lewis Acids
3.11 Conclusions
Acknowledgments
References
Chapter 4: Copper-based Chiral Lewis Acids
4.1 Introduction
4.2 Conjugate Additions
4.3 Mannich-Type Reaction
4.4 Aldol-Type Reactions
4.5 Asymmetric Friedel–Crafts Alkylation
4.6 Cycloadditions
4.7 Cyclization Reactions
4.8 Kinetic Resolution
4.9 Desymmetrization
4.10 Trifluoromethylation
4.11 Halogenation
4.12 Reductions
4.13 Other Reactions
4.14 Conclusions
References
Chapter 5: Zinc-based Chiral Lewis Acids
5.1 Introduction
5.2 Zinc Abundance in Nature
5.3 Carbon–Carbon Bond Formation
5.4 Carbon–Hydrogen Bond Formation
5.5 Carbon–Oxygen Bond Formation
5.6 Carbon–Phosphorus Bond Formation
References
Chapter 6: From Noble Metals to Fe-, Co-, and Ni-based Catalysts: A Case Study of Asymmetric Reductions
6.1 Introduction
6.2 Brief Historical Background – “From the Golden Age to the Iron Age”
6.3 Development of New Methods for Asymmetric Reduction
6.4 Some Mechanistic Considerations
6.5 Reduction of C═C Bond – Asymmetric Hydrogenation
6.6 Asymmetric Reductions of C═O bonds
6.7 Conclusions
References
Chapter 7: Chiral Complexes with Carbophilic Lewis Acids Based on Copper, Silver, and Gold
7.1 Introduction
7.2 Enantioselective Copper Catalysis
7.3 Enantioselective Gold Catalysis
7.4 Enantioselective Silver Catalysis
7.5 Conclusions
References
Chapter 8: Chiral Rare Earth Lewis Acids
8.1 Introduction
8.2 Monofunctional Lewis Acid Catalysis
8.3 Heterobimetallic Catalysts
8.4 Conclusions
References
Chapter 9: Water-compatible Chiral Lewis Acids
9.1 Discovery of Water-compatible Lewis Acids
9.2 Definition and Fundamentals of Water-compatible Lewis Acids
9.3 Chiral Induction by Lewis Acid in Aqueous Environments
9.4 1,2-Addition to C═O Double Bond
9.5 1,2-Addition to C═N Bond
9.6 Cycloadditions
9.7 Addition to Epoxides
9.8 Conjugate Additions
9.9 Conclusions
References
Chapter 10: Cooperative Lewis Acids and Aminocatalysis
10.1 Introduction
10.2 Conclusions
References
Index
End User License Agreement
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Guide
Cover
Table of Contents
Preface
Begin Reading
List of Illustrations
Chapter 1: Alkaline-Earth Metal-Based Chiral Lewis Acids
Figure 1.1 Types of alkaline earth metal complexes.
Scheme 1.1 A Box–calcium complex-catalyzed [3+2] cycloaddition reaction of amino acid Schiff bases with α,β-unsaturated carbonyl compounds [1, 4].
Figure 1.2 Type II chiral alkaline earth metal complexes. Alkaline earth metal–chiral bisoxazoline complexes [1, 3].
Figure 1.2 Catalytic [3+2] cycloaddition reaction using a Box–calcium complex prepared from calcium amide and bisoxazoline derivative.
Scheme 1.3 Asymmetric Diels–Alder reaction of a silyloxydiene with fumarate catalyzed by chiral alkaline earth metal complexes.
Figure 1.3 The catalytic cycle of asymmetric Diels–Alder-type reaction postulated by Shibasaki.
Scheme 1.4 Asymmetric hetero-Diels–Alder reactions of heterodienes with vinyl ethers.
Scheme 1.5 Chiral strontium complex-catalyzed asymmetric Mannich reaction of sulfonylimidates.
Scheme 1.6 The calcium-catalyzed asymmetric addition of malonates to α,β-unsaturated ketones.
Scheme 1.7 The calcium-catalyzed epoxidation of chalcones.
Scheme 1.8 The asymmetric addition of β-ketoesters to methyl vinyl ketone.
Scheme 1.9 The Box–calcium-catalyzed addition of protected glycines to Michael acceptors.
Scheme 1.10 The asymmetric synthesis of substituted glutamic acids.
Scheme 1.11 CaCl
2
as the basis of a moisture-tolerant catalytic system.
Scheme 1.12 Formation of quaternary stereocenters in the synthesis of glutamic acid derivatives from azlactones.
Scheme 1.13 The asymmetric addition of malonates to nitroalkenes.
Scheme 1.14 Kobayashi's approach to flow synthesis of rolipram.
Scheme 1.15 The asymmetric addition of malonates to acrylamides.
Scheme 1.16 The divergent amination of enamides.
Scheme 1.17 The asymmetric synthesis of disubstituted oxindoles.
Scheme 1.18 Strontium-catalyzed addition of malonates to chalcones.
Scheme 1.19 The formation of active strontium species.
Scheme 1.20 Quaternary stereocenter formation in the course of asymmetric cyanation.
Scheme 1.21 The enantioselective rearrangement of cyanohydrins with a Sr catalyst.
Scheme 1.22 The Friedel–Crafts-type alkylation of indoles with chalcones.
Scheme 1.23 The asymmetric oxidation of oxindoles.
Scheme 1.24 The asymmetric aminobromination of alkenes.
Scheme 1.25 The desymmetrization of aziridines with thiocyanate.
Chapter 2: Titanium-Based Chiral Lewis Acids
Scheme 2.1 Asymmetric addition of diethylzinc to benzaldehyde in the presence of Ti catalyst.
Scheme 2.2 Synthesis of α-diazo-β-hydroxyesters via addition of ethyl diazoacetate to aldehyde.
Scheme 2.3 Ti
IV
-catalyzed enantioselective sequential condensation/cyclization reaction of enamine and trifluoropyruvate.
Scheme 2.4 Transition-state model for Ti
IV
-catalyzed enantioselective sequential condensation/cyclization reaction of enamine and trifluoropyruvate.
Scheme 2.5 Enantioselective monofluoromethylation of aldehydes catalyzed by a bifunctional cinchona alkaloid-derived thiourea(
L2
)–titanium complex.
Scheme 2.6 Asymmetric catalytic conjugate cyanation of diethyl alkylidenemalonate with ethyl cyanoformate.
Scheme 2.7 Conjugate cyanation of nitroolefins catalyzed by a salen(L5)–titanium catalyst.
Scheme 2.8 Formation of silyl nitronate intermediate and derivation of conjugate adduct to β-amino acid.
Scheme 2.9 Enantioselective epoxidation of olefins catalyzed by a di-μ-oxo titanium–
trans
-1,2-diamino-cyclohexane-salalen catalyst.
Scheme 2.10 Synthesis of versatile "symmetrical" or "nonsymmetrical" dihydrosalen (salalen) ligands.
Scheme 2.11 Deactivation of the Ti(salalen) catalyst by aqueous hydrogen peroxide with subsequent loss of water.
Scheme 2.12 Various ligands for the titanium-catalyzed asymmetric epoxidation of olefins with aqueous hydrogen peroxide.
Scheme 2.13 Asymmetric epoxidation of conjugated olefins in the presence of the titanium-full-reduced salen catalyst.
Scheme 2.14 Proline-derived 1,2-diamine for asymmetric epoxidation of styrene derivatives.
Scheme 2.15 Asymmetric Darzens reaction between diazoacetamides and aldehydes catalyzed by BINOL–Ti
IV
complex.
Scheme 2.16 Plausible mechanism for asymmetric Darzens reaction between diazoacetamides and aldehydes.
Scheme 2.17 Titanium-catalyzed ring opening of various
meso
-aziridines with anilines.
Scheme 2.18 Ga–Ti–salen catalyst for asymmetric ring opening of
meso
-epoxides with aryl selenols and thiols.
Scheme 2.19 Schiff base ligands for asymmetric ring opening of cyclohexene epoxides.
Scheme 2.20 Kagan and Modena’s oxidation of aryl sulfides to sulfoxides.
Scheme 2.21 Application of Ti(O
i
Pr)
4
/diethyl tartrate for esomeprazole synthesis.
Scheme 2.22 Tartrate ester ligands for asymmetric sulfoxidation reactions.
Scheme 2.23 Hydrobenzoin-derived ligand for Ti(O
i
Pr)
4
-catalyzed preparation of 1
H
-benzimidazolyl pyridinylmethyl sulfoxides.
Scheme 2.24 Various ligands for asymmetric catalytic sulfoxidation.
Scheme 2.25 Asymmetric oxidation of 1
H
-benzimidazolyl pyridinylmethyl sulfide with CHP.
Scheme 2.26 Hetero-Diels–Alder reaction of
trans
-1-methoxy-2-methyl-3-trimethylsiloxybuta-1,3-diene with various aldehydes.
Scheme 2.27 Titanium-catalyzed enantioselective intramolecular Heck/Aza–Diels–Alder cycloaddition.
Scheme 2.28 TiCl
2
(TADDOLato) complex for enantioselective fluorination of β-keto esters.
Scheme 2.29 Ti(TADDOLato) complex for asymmetric sulfenylation of β-keto esters.
Scheme 2.30 Titanium–BINOLate complex-catalyzed enantioselective intramolecular cyclization of
N
-aryl diazoamides.
Scheme 2.31 β-Hydroxyamide (
L27
)/titanium complex for asymmetric reduction of ketones.
Scheme 2.32 Preparation of 2-methylcoumarans by asymmetric hydroalkoxylation of alkenes.
Scheme 2.33 Asymmetric reductive coupling of aromatic aldehydes.
Scheme 2.34 Enantioselective intramolecular reductive coupling of diimines to 2,3-diarylpiperazines.
Scheme 2.35 Enantioselective titanium(III)-catalyzed reductive cyclization of ketonitriles to cyclic α
-
hydroxyketones.
Scheme 2.36 A plausible mechanism of enantioselective titanium(III)-catalyzed reductive cyclization of ketonitriles.
Scheme 2.37 Synthesis of the BINOL-derived bis-titanium complexes with electron-withdrawing groups at 6,6′-positions.
Scheme 2.38 Asymmetric 1,3-dipolar cycloaddition of nitrones and unsaturated aldehydes.
Scheme 2.39 Conversion of the products of 1,3-dipolar cycloaddition of nitrones and unsaturated aldehydes to the corresponding β-amino acid esters.
Scheme 2.40 Enantioselective Friedel–Crafts alkylation reactions of indole with ethyl glyoxylate in the presence of (
S
)-BINOL–Ti
IV
(2 : 1) complex.
Scheme 2.41 Asymmetric Friedel–Crafts alkylation reaction of heteroaromatic compounds with glyoxylate.
Scheme 2.42 Application of Jurczak’s protocol of asymmetric Friedel–Crafts alkylation for the synthesis of duloxetine.
Chapter 3: Iron-based Chiral Lewis Acids
Figure 3.1 Fe-porphyrin complexes.
Scheme 3.1 Chiral porphyrins.
Figure 3.2 Dinuclear Fe bipyridine complex for the oxidation of prochiral sulfides by hydrogen peroxide.
Scheme 3.2 Yamamoto's chiral Fe
II
-bipyridine complex – asymmetric epoxidation of β,β-disubstituted enones and nonactivated olefins.
Scheme 3.3 Chiral Fe
III
-sexipyridine complex used for epoxidation of alkenes.
Scheme 3.4 Iron-catalyzed asymmetric cyclopropanation of styrene with ethyl diazoacetate.
Scheme 3.5 Catalytic asymmetric Mukaiyama aldol reaction with various aldehydes and Fe(DS)
2
-catalyzed Mukaiyama aldol reaction in water.
Scheme 3.6 Catalytic asymmetric
meso
-epoxide opening reaction with aniline derivatives and indoles.
Scheme 3.7 Fe
III
-catalyzed asymmetric sulfide oxidation with aqueous hydrogen peroxide.
Scheme 3.8 Dinuclear chiral Fe-complex and its application in asymmetric hydrophosphorylation of aldehydes (a) and camphor-derived Fe-complex (b).
Scheme 3.9 Asymmetric Fe-catalyzed oxidations using Schiff base ligands.
Figure 3.3 Fe
III
-
salen
catalysts (a) and chiral trinuclear Fe
III
-
triplesalen
complex (b).
Scheme 3.10
cis
-2,5-Diaminobicyclo[2.2.2]octane, as new scaffold for asymmetric synthesis via Fe-
salens
.
Scheme 3.11 Enantioselective oxidation of sulfides in water (a) and asymmetric aerobic oxidative coupling of 3-substituted naphthols (b).
Scheme 3.12 Aerobic kinetic resolution of secondary alcohols using air as oxidant (a) and oxidative dearomatization of 1,3-disubstituted 2-naphthols using nitroalkanes (b), asymmetric tandem synthesis of spirocyclic (2
H
)-dihydrobenzofurans (c).
Scheme 3.13 Fe
III
-
salan
-catalyzed enantioselective α-fluorination and α-hydroxylation reactions.
Scheme 3.14 Fe
III
-catalyzed enantioselective Diels–Alder reaction.
Figure 3.4 Chiral
diamino-bis(oxazoline)
ligands were prepared by Pfaltz.
Scheme 3.15 Fe
II
-catalyzed asymmetric O─H bond insertion reactions and C─H functionalization of indoles (a), asymmetric intramolecular Fe
II
-catalyzed cyclopropanation of α-diazoesters (b).
Scheme 3.16 Asymmetric epoxidations of alkene with catalytic iron Lewis acids.
Scheme 3.17 Fe-catalyzed asymmetric oxyamination reaction of olefins.
Scheme 3.18 Enantioselective azidation reaction of β-keto esters.
Scheme 3.19 Fe-catalyzed asymmetric intramolecular olefin aminohydroxylation (a) and stereoconvergent and enantioselective olefin aminofluorination (b).
Scheme 3.20 Asymmetric oxidation of aromatic sulfides using chiral Fe/6,6ʹ-bis(oxazolinyl)-2, 2 -bipyridine.
Scheme 3.21 Catalytic enantioselective Diels–Alder reaction.
Scheme 3.22 Asymmetric Mukaiyama aldol reaction in aqueous media.
Scheme 3.23 Asymmetric hydrosilylation of aryl ketones catalyzed by Fe-
pybox
and Fe-
bopa
Lewis acids.
Scheme 3.24 Chiral Fe
II
-
bis(oxazolinyl)
catalysts and their use in asymmetric hydrosilylation.
Scheme 3.25 Fe
II
-catalyzed enantioselective conjugate addition of thiols.
Scheme 3.26 Preparation of Fe
II
-
phebox
and
pybox
ligands for asymmetic hydrosilylation.
Scheme 3.27 Asymmetric aziridination of styrene.
Scheme 3.28 Asymmetric Nazarov cyclization catalyzed by an Fe
II
salt in the presence of a
pybox
ligand.
Scheme 3.29 Fe
III
-catalyzed enantioselective sulfimidation (a) and resolution of racemic sulfoxides through catalytic asymmetric nitrene-transfer reactions (b).
Scheme 3.30 Fe-catalyzed asymmetric epoxidation of various aromatic alkenes.
Scheme 3.31 Effect of iron and primary amines on
Warfarin
synthesis.
Scheme 3.32 Selective aliphatic C─H activation.
Scheme 3.33 Chiral Fe
II
-Lewis acids capable of promoting asymmetric olefin
cis
-dihydroxylation and catalyzed
cis
-dihydroxylation of olefins with H
2
O
2
.
Scheme 3.34 Chiral Fe
II
-Lewis acid complexes for the asymmetric epoxidation of enones with H
2
O
2
.
Scheme 3.35 Chiral Fe
II
-complexes used for epoxidation of α,β-enones.
Figure 3.5 Chiral Fe
II
Lewis acid complexes reported by Klein Gebbink.
Scheme 3.36 Chiral Fe
II
-complexes used for hydrosilylation.
Scheme 3.37 Chiral diamine ligands disclosed by Togni.
Figure 3.6 Nonsymmetrical Fe
II
Lewis acids for the enantioselective epoxidation of enones.
Scheme 3.38 Synthesis of chiral cyclopentadienyl-Fe
II
Lewis acids (a) and enantioselective Diels–Alder reaction (b).
Scheme 3.39 Asymmetric 1,3-dipolar cycloadditions between nitrones and methacrolein.
Scheme 3.40 Enantioselective Diels–Alder reaction using
P
-chirogenic diphosphine oxide.
Figure 3.7 Enantiopure PNNP ligands used for Gao's
in situ
-formed iron Lewis acid catalyst for transfer hydrogenation of aromatic and hetereoaromatic ketones.
Scheme 3.41 Use of an Fe-diphosphine catalyst for asymmetric hydrosilylation of ketones.
Scheme 3.42 Structure of an iron diphosphine Lewis acid and asymmetric transfer hydrogenation of
N
-(diphenylphosphinyl)ketimine.
Scheme 3.43 Synthesis of an Fe precatalyst for asymmetric transfer hydrosilylation and asymmetric hydrogenation of ketones.
Figure 3.8 Iron carbonyl Lewis acids for hydrogenation and transfer hydrogenation of ketones.
Scheme 3.44 Asymmetric hydrogenation reaction of ketones and imines.
Scheme 3.45 Iron complexes as intermediates in hydrogenation reactions.
Scheme 3.46 Iron isonitrile complexes from
C
2
-symmetric diamino macrocyclic ligands for the asymmetric transfer hydrogenation.
Scheme 3.47 Chiral Fe
II
NPPN complexes for the asymmetric Strecker reaction of azomethine imines.
Scheme 3.48 Synthesis of bis(phosphine) iron dialkyl complexes.
Scheme 3.49 Catalytic asymmetric Mannich-type reactions using a chiral Fe-
binol
catalyst.
Scheme 3.50 Oxidative kinetic resolution of benzoins catalyzed by chiral Fe Lewis acid.
Scheme 3.51 Asymmetric Friedel–Crafts alkylation of indoles.
Scheme 3.52 Fe
III
-catalyzed enantioselective carbometalation.
Figure 3.9 Knölker Fe-derived systems.
Scheme 3.53 (Cyclopentadienone)iron complexes in the catalytic asymmetric hydrogenation of ketones.
Scheme 3.54 Fe
III
-bis(sulfoxide)-catalyzed Diels–Alder reaction.
Scheme 3.55 Fe-
N
-heterocyclic carbene complexes for enantioselective alkylation of an aromatic aldehyde.
Scheme 3.56 Fe
III
-catalyzed asymmetric haloamination.
Scheme 3.57 Synthesis of Fe
II
-bis(isonitrile) Lewis acids.
Scheme 3.58 Fe
II
-catalyzed enantioselective hydrosilylation of 1,1-disubstituted alkenes.
Chapter 4: Copper-based Chiral Lewis Acids
Scheme 4.1 Conjugate addition of organoboronates to alkylidene cyanoacetates in the presence of copper and
N
-heterocyclic carbene catalyst.
Scheme 4.2 Enantioselective conjugate addition of alkylborons to imidazol-2-yl α,β-unsaturated ketone in the presence of copper(I)/
N
-heterocyclic carbene catalyst.
Scheme 4.3 Copper(II)-catalyzed enantioselective addition of diboron to α,β-unsaturated carbonyl compounds.
Scheme 4.4 Copper(II)-catalyzed enantioselective β-borylation of α,β-unsaturated imines in water.
Scheme 4.5 Copper(II)-catalyzed enantioselective β-borylation of α,β-unsaturated nitriles in water.
Scheme 4.6 Copper-carbene-catalyzed 1,2-addition of dialkyl zinc to α,β-unsaturated
N
-tosylaldimines.
Scheme 4.7 Copper-catalyzed enantioselective Mukaiyama–Michael addition of 3-(trialkyl-silanoxy)-2-diazo-butenoate to α,β-unsaturated 2-acylimidazoles.
Scheme 4.8 Preparation of β
2,2,3
-amino acid precursors via copper(I)-catalyzed decarboxylative Mannich-type reaction.
Scheme 4.9 Preparation of β-amino acid precursors via copper-catalyzed Mannich-type reaction between α- and β-fluorine-functionalized 7-azaindoline amides and imines.
Scheme 4.10 Copper(II)-catalyzed asymmetric Mannich-type reaction of 2-fluoro-1,3-diketones/hydrates and isatin-derived ketimines.
Scheme 4.11 Copper(I)-conjugated Brønsted base catalyst for incorporation of ketones to cyclic hemiaminals.
Scheme 4.12 Asymmetric aldol reaction between aliphatic aldehydes and thiolactam.
Scheme 4.13 Synthesis of α-oxyamides via a key step of enantioselective Henry reaction.
Scheme 4.14 Copper(II)-BOX-catalyzed aza-Henry reaction between isatin
N
-Boc ketimines and nitro alkanes.
Scheme 4.15 Anti-selective asymmetric Henry reaction for the formation of various β-nitroalcohols.
Scheme 4.16 Copper-sulfoximine-catalyzed vinylogous Mukaiyama aldol reaction of α-ketoesters and achiral
N
,
O
-silylated ketene aminals.
Scheme 4.17 Schiff base-copper(II)-catalyzed Friedel–Crafts alkylation of pyrroles with nitroalkenes.
Scheme 4.18 Copper(II)-catalyzed enantioselective Friedel–Crafts alkylation of pyrrole with β,γ-unsaturated α-ketoesters.
Scheme 4.19 Copper(II)/bisoxazoline-catalyzed Friedel–Crafts alkylation reaction of styrenes with trifluoropyruvates.
Scheme 4.20 Synthesis of β-aryl enones via copper(II)/bisoxazoline-catalyzed Friedel–Crafts alkylation of pyrroles and indoles with β′-hydroxy enones.
Scheme 4.21 Copper(II)-catalyzed asymmetric Diels–Alder reaction of 1-hydrazinodienes with various dienophiles.
Scheme 4.22 Copper-catalyzed asymmetric hetero-Diels–Alder reaction of β,γ-unsaturated α-ketoesters with Danishefsky’s diene.
Scheme 4.23 Copper-catalyzed asymmetric hetero-Diels–Alder reaction of Danishefsky’s diene with glyoxals.
Scheme 4.24 π-Cation copper complex for enantioselective 1,3-dipolar cycloaddition of nitrones with acetylene derivatives.
Scheme 4.25 Cu(II)-BOX-catalyzed 1,3-dipolar cycloaddition reaction of nitrones with 2-alkenoyl pyridine-
N
-oxide.
Scheme 4.26 Bis-(imidazolidine)pyridine-Cu(OTf)
2
complex for
endo
-selective [3+2] cycloaddition reaction of iminoesters with methyleneindolinones.
Scheme 4.27 [3+2] Cycloaddition of allyltin derivatives with nitrosopyridine.
Scheme 4.28 Copper triflate-catalyzed azide–alkene cycloaddition.
Scheme 4.29 Copper/(
R
)-Tol-BINAP-catalyzed [4+1] cycloaddition of azoalkenes with sulfur ylides.
Scheme 4.30 Synthesis of piperidine derivatives via [6+3] cycloaddition reaction between azomethine ylides and unsymmetrical fulvenes.
Scheme 4.31 [3+2] Annulation of indoles and 2-aryl-
N
-tosylaziridines in the presence of copper(I)-diphosphine ligand complex as the catalyst.
Scheme 4.32 Synthesis of chiral isochromenes via copper(II)/phosphate-catalyzed intramolecular cyclization/asymmetric transfer hydrogenation sequence of
o
-alkynylacetophenone derivatives.
Scheme 4.33 Copper(I)-catalyzed enantioselective metallo-organocatalyzed carbocyclizations of formyl-alkynes.
Scheme 4.34 Copper(II)/BINOL complex for the synthesis of 2-alkyl and 2-aryl dihydroquinolones.
Scheme 4.35 Synthesis of useful benzo[
f
]-indole-4,9-dione derivatives via copper-catalyzed reaction of naphthaquinone and β-enaminones.
Scheme 4.36 Reductive aldol cyclization of ketoenethioate derivatives of 1,3-cyclopentanedione.
Scheme 4.37 Cyclopropanation of α-methylstyrene in the presence of supported hydrogen-bonded chiral copper(I) complex as the catalyst.
Scheme 4.38 Copper triflate/4,4′-bisoxazoline complex-catalyzed cyclopropanation of styrene.
Scheme 4.39 Crispine A synthesis via copper-triggered ring opening of phenyl-cyclopropyl ketone.
Scheme 4.40 One-pot multicatalytic system for the asymmetric synthesis of 1,2,3,4-tetrahydrocarbazoles.
Scheme 4.41 Copper-catalyzed enantioselective Diels–Alder cycloaddition reaction for the kinetic resolution of racemic pyrazolidinones.
Scheme 4.42 Synthesis of chiral oxazolines through asymmetric desymmetrization of 1,3-diols by chiral copper(II)-(
R
,
R
)-Ph-Box catalyst.
Scheme 4.43 Copper(II)-catalyzed trifluoromethylation of
N
-aryl imines with trifluoromethyltrimethylsilane.
Scheme 4.44 Copper-Boxmi-catalyzed enantioselective trifluoromethylthiolation of β-ketoesters using benziodoxole-based transfer reagent.
Scheme 4.45 Enantioselective α-chlorination of β-ketoesters.
Scheme 4.46
gem
-Chlorofluorination of active methylene compounds.
Scheme 4.47 Enantioselective reduction of α-ketoamides.
Scheme 4.48 Synthesis of (
E
) alkenyl silanes via regioselective hydrosilylation of allenes.
Scheme 4.49 Copper(II)-catalyzed intramolecular cyclization of sulfonamides.
Scheme 4.50 Synthesis of enantiomerically enriched 1-ethynyl-isoindolines in the presence of copper/pybox complex.
Scheme 4.51 Copper-catalyzed aziridination of alkenes.
Scheme 4.52 Copper-catalyzed asymmetric allylation of chiral
N-tert
-butyl-sulfinyl imines.
Scheme 4.53 Synthesis of benzocyclohepta[
b
]indoles via annulation of two molecules of 3-(1
H
-isochromen-1-yl)-1
H
-indole.
Scheme 4.54 Intermolecular three-component amino oxygenation of olefins catalyzed by copper triflate.
Scheme 4.55 Copper(II)-bisoxazoline-catalyzed asymmetric α-arylation of
N
-acyloxazolidinones.
Scheme 4.56 Allylic oxidation of cycloalkenes in the presence of CuPF
6
/bi-
o
-tolyl bisoxazoline.
Scheme 4.57 Oxaziridine-mediated enantioselective aminohydroxylation of styrenes catalyzed by copper(II)/bisoxazoline complex.
Scheme 4.58 Copper(I)/bisoxazoline-catalyzed intramolecular C─H insertion of α-diazosulfones for the synthesis of six-membered ring cyclic sulfones.
Scheme 4.59 Copper(I)/imidazoindolephosphine complex-catalyzed O─H carbenoid insertion reaction of phenols to α-diazopropionates.
Scheme 4.60 Copper acetate-catalyzed asymmetric alkynylation reaction of azomethine imines.
Scheme 4.61 Copper-catalyzed asymmetric direct alkynylation of benzopyranyl acetals.
Scheme 4.62 Copper(I)-catalyzed addition of terminal alkynes to isochroman ketals.
Chapter 5: Zinc-based Chiral Lewis Acids
Scheme 5.1 Mechanism of aldol reaction activated by type II aldolase.
Scheme 5.2 Example of aldol reaction catalyst based on zinc complexes.
Scheme 5.3 Aldol reaction of acetone
8
activated by Zn(NO
3
)
2
–
7
complex.
Scheme 5.4 Zinc–proline catalytic system applied by Darbre.
Scheme 5.5 Proposed transition states for zinc–proline activation of aldol reaction.
Scheme 5.6 Examples of prolinamide ligands for zinc-activated aldol reaction.
Scheme 5.7 Aza-crown catalyst developed by Aoki.
Scheme 5.8 Mannich-type reaction developed by Kobayashi.
Scheme 5.9 Mechanism proposed by Kobayashi for Mannich-type reaction.
Scheme 5.10 Inverted diastereoselectivity observed for different
N
-protecting groups.
Scheme 5.11 Asymmetric Mannich reaction of fluoroindanone derivatives with imines.
Scheme 5.12 Asymmetric Mannich reaction of silyl ketene imines with ketimines.
Scheme 5.13 Direct vinylogous Mannich reaction of ketimines with γ-butenolide
21
.
Scheme 5.14 Soai conjugate addition of dialkylzinc to prochiral enones.
Scheme 5.15 Michael addition activated by Shibasaki catalyst.
Scheme 5.16 Michael addition of coumarin derivatives activated by pybox–zinc complex.
Scheme 5.17 Conjugate addition of aryloacetonitriles to alkylidene malonates.
Scheme 5.18 Nitro-Michael addition of nitroethane
29
to nitroalkenes.
Scheme 5.19 Nitro-Michael reaction activated by ProPhenol catalyst
4
.
Scheme 5.20 Aza-Michael addition activated by the novel type ProPhenol catalyst
32
.
Scheme 5.21 Selected examples of ligands applied in the addition of organometallic species to carbonyl compounds.
Scheme 5.22 Soai autocatalytic reaction.
Scheme 5.23 Diels–Alder reaction developed by Takacs.
Scheme 5.24 Diels–Alder reaction developed by Jørgensen.
Scheme 5.25 Hetero-Diels–Alder reaction of
N
-sulfinyl dienophiles.
Scheme 5.26 HDA reaction between
N
-sulfinyl dienophiles and various dienes.
Scheme 5.27 Aza-Diels–Alder reaction of Danishefsky diene
75
catalyzed by zinc(II)–BINOL complex.
Scheme 5.28 [4+2] Cycloaddition of 1-azadienes and nitro-alkenes.
Scheme 5.29 Diastereoselective [3+2] cycloaddition reported by Jørgensen.
Scheme 5.30 Cycloaddition reported by Dogan and Garner with proposed transition state.
Scheme 5.31 First asymmetric Friedel–Crafts reaction catalyzed by zinc complexes.
Scheme 5.32 Asymmetric Friedel–Crafts reaction developed by Guiry.
Scheme 5.33 Asymmetric Friedel–Crafts reaction developed by Du.
Scheme 5.34 Asymmetric F–C reaction of 2-methoxyfuran
68
with various nitroalkenes.
Scheme 5.35 Proposed transition states for F–C alkylation activated by both Zn–
69
(
TS-A
) and Zn–
30a
(
TS-B
) complexes.
Scheme 5.36 Asymmetric F–C reaction of pyrrole activated by ProPhenol catalyst
4
.
Scheme 5.37 Enantioselective Friedel–Crafts alkylation of indoles catalyzed by Zn–
71
complex.
Scheme 5.38 One-pot synthesis of 2-amino-4-(indol-3-yl)-4
H
-chromenes in a domino reaction.
Scheme 5.39 Enantioselective Friedel–Crafts alkylation of pyrrole
73
catalyzed by Zn–
27
complex.
Scheme 5.40 Enantioselective Friedel–Crafts alkylation catalyzed by Zn–
74
complex.
Scheme 5.41 Asymmetric aza-Friedel–Crafts reaction activated by
4
developed by Hui.
Scheme 5.42 Asymmetric aza-Friedel–Crafts reaction activated by
4
developed by Wang.
Scheme 5.44 Various ligands applied for zinc-based asymmetric hydrosilylation of ketones.
Scheme 5.43 Mechanisms of hydrosilylation of ketones as postulated by Mimoun.
Scheme 5.45 The development of Zn-based hydrosilylation of imines.
Scheme 5.46 Zn–diamine catalyst for hydrosilylation of
N
-DPP-imines under protic (
A
) and non-protic (
B
) conditions.
Scheme 5.47 [Zn]-catalyzed direct hydrogenation of imines.
Scheme 5.48 Epoxidation of various olefins under Enders’ conditions.
Scheme 5.49 Epoxidation of various olefins by Lewiński.
Scheme 5.50 Mechanism for the enantioselective epoxidation of enones.
Scheme 5.51 Enantioselective 1,4-additions of phosphorus nucleophiles to α,β-unsaturated systems catalyzed in the presence of dinuclear zinc catalysts.
Scheme 5.52 Mechanism of enantioselective phospha-Michael addition catalyzed by dinuclear Zn–ProPhenol catalyst.
Scheme 5.53 Phospha-Mannich reaction of various
N
-sulfinylimines with zinc-activated dialkyl phosphine oxides.
Scheme 5.54 Enantioselective three-component reaction of various aldehydes,
p
-anisidine and bis(
ortho
-methoxyphenyl) phosphite using pybim–Zn(II).
Scheme 5.55 The catalytic asymmetric hydrophosphonylation of aldehydes in the presence of homobimetallic Zn complex.
Scheme 5.56 Mechanism of enantioselective hydrophosphonylation of aldehydes in the presence of homobimetallic zinc complex.
Chapter 6: From Noble Metals to Fe-, Co-, and Ni-based Catalysts: A Case Study of Asymmetric Reductions
Scheme 6.1 Different methods of reduction of various prochiral unsaturated compounds.
Figure 6.1 Rhodium- and iridium-based catalysts for homogenous hydrogenation of alkenes.
Figure 6.2 Various types of chiral ligands used in metal-catalyzed asymmetric reductions.
Scheme 6.2 Some of the first studies on the asymmetric hydrogenation of alkenes using chiral phosphine ligands.
Figure 6.3 The possible ways for developing new methods of asymmetric reduction.
Scheme 6.18 [Cu-bisoxazoline]-catalyzed ATH of keto-esters.
Scheme 6.3 Mechanism of [Rh-diphosphine]-catalyzed AH of
N
-acetyl-dehydrophenylalanine.
Scheme 6.4 Proposed mechanism for the AH and ATH of ketones catalyzed by bifunctional Ru-BINAP complex.
Scheme 6.5 Proposed mechanism for the ATH of ketones catalyzed by Fe-PNNP complexes.
Scheme 6.6 Proposed mechanisms for the [Zn-diamine]-catalyzed AHS of ketones (a) and AHS of imines (b).
Scheme 6.7 Plausible mechanism of the Ir-catalyzed AH of quinolines.
Figure 6.4 Different types of functionalized olefins that undergo Rh-catalyzed asymmetric hydrogenation with excellent yields and
ee
’s (90–100%).
Scheme 6.8 Enantioselective hydrogenation of (
Z
)-α-(acylamino)cinnamic acid and esters gives opposite enantiomers of
N
-protected phenylalanine when carried out in the presence of rhodium and ruthenium BINAP and ChiraPhos catalysts.
Scheme 6.9 Asymmetric hydrogenation of 2-phenyl-1-butene by titanocene complexes in presence of Red-Al – Li[H
2
Al(OCH
2
CH
2
OCH
3
)
2
] as cocatalyst.
Scheme 6.10 Fe-catalyzed AH of ketones.
Scheme 6.11 [Fe-P
2
N
4
-ligand]-catalyzed AH of ketones.
Scheme 6.12 AH of ketones catalyzed by Cu-BDPP complex.
Scheme 6.13 Cu-catalyzed AH of ketones.
Scheme 6.14 Diastereoselective syntesis of anti-β-amino alcohols through dynamic kinetic resolution and asymmetric hydrogenation.
Scheme 6.15 Os-catalyzed AH of ketones.
Scheme 6.16 ATH of ketones catalyzed by [Fe-PNNP] complexes.
Scheme 6.17 [Ni-PNO]-catalyzed ATH of ketones.
Scheme 6.19 Hydrosilylation of prochiral ketones followed by hydrolysis of silyl ether intermediate leads to chiral secondary alcohols.
Figure 6.5 Structures of chiral ligands used for the AHS of ketones.
Figure 6.6 General structures of potential prochiral substrates for asymmetric reduction and approximate numbers of available chiral compounds.
Figure 6.7 Simple chiral ligand toolbox for asymmetric reduction.
Chapter 7: Chiral Complexes with Carbophilic Lewis Acids Based on Copper, Silver, and Gold
Scheme 7.1 Phosphoramidites ligands for Cu-catalyzed additions of dialkylzinc to enones.
Scheme 7.2 Cu-catalyzed additions of dialkylzinc reagents to enones.
Scheme 7.3 Cu–phosphoramidite-catalyzed conjugate addition of dialkylzincs to acyclic nitroalkenes.
Scheme 7.4 Cu-catalyzed borylative cyclization of 1,6-enynes.
Scheme 7.5 Bisphenyl-derived phosphoramidites for the addition of organoaluminum reagents to enones.
Scheme 7.6 Cu-catalyzed addtion of trimethylaluminum in the synthesis of taxadienone.
Scheme 7.7 Copper–phosphoramidite complexes in the conjugate addition of organozirconium.
Scheme 7.8 Peptide-based ligands for Cu-catalyzed conjugate additions of dialkylzinc to enones.
Scheme 7.9 Cu/Taniaphos-catalyzed enantioselective conjugate additions of Grignard reagents to cyclic enones.
Scheme 7.10 Proposed mechanism of the 1,4-addition of Grignard reagents to enones.
Scheme 7.11 Conjugate addition of Grignard reagent to alkenyl-substituted aromatic heterocycles.
Scheme 7.12 Ferrocene-based ligands for intermolecular (a) and intramolecular (b) conjugate reductions of enones.
Scheme 7.13 Ferrocenyl diphosphanes for CuHL*-mediated (a) reductive coupling of vinylazaarenes with ketones and (b) tandem borylative aldol reaction.
Scheme 7.14 Ferrocenyl diphosphanes for the catalytic conjugation borylations of (a) cyclic enones, (b) unsaturated esters and nitriles, and (c) boron-containing unsaturated esters.
Scheme 7.15 BINAP-derived-ligand-mediated conjugate additions of Grignard reagents to (a) unsaturated esters, (b) 3-boronyl unsaturated esters or thioesters, and (c) 4-chloro-α,β-unsaturated esters, thioesters, and ketones.
Figure 7.1 Various ligands applied in Cu-catalyzed conjugate additions.
Figure 7.2 Various highly enantioselective phosphorus-based ligands.
Scheme 7.16 Cu complexes with
N
-heterocyclic carbenes for the conjugate addition of dialkyl and diarylzinc reagents to enones and keto esters.
Scheme 7.17 Cu-NHC-catalyzed conjugate addition of alkylboranes to alkenes and the postulated mechanism of the reaction.
Scheme 7.18 Cu(I)/ferrocenyl amine complexes for allylic substitution with dialkylzinc reagent.
Scheme 7.19 Cu-catalyzed alkylation of allyl halides.
Scheme 7.20 Cu-catalyzed transformation of the enal to enol acetate with subsequent allylic substitution with Grignard reagents.
Scheme 7.21 Cu-catalyzed allylic alkylation with (a) Grignard and (b) organozirconium reagents.
Scheme 7.22 Allylic substitution with Grignard reagents using Cu–Taniaphos complex.
Scheme 7.23 Cu(I) complex for substitution of propargylic esters.
Scheme 7.24 Enantioselective allylic alkylation using alkylboranes and the postulated mechanism of the reaction.
Scheme 7.25 Cu/QuinoxP*-catalyzed allylic boryl substitution.
Scheme 7.26 Application of copper complexes with NHC in allylic alkylation.
Scheme 7.27 Cu/NHC-catalyzed allylic alkylation with alkenylaluminum reagent.
Scheme 7.28 Cu complex with NHC ligands for arylation of allyl phosphonates.
Scheme 7.29 Cu-catalyzed allylic (a) boronation and (b) silylation.
Scheme 7.30 Copper complexes for enantioselective amination of alkenes.
Scheme 7.31 CuH-catalyzed substitution of allylic ethers and esters.
Scheme 7.32 Cu-mediated 1,2-reduction of unsaturated aldehydes followed by the amination of the corresponding allylic alcohol.
Scheme 7.33 Copper hydride-mediated transformations of unactivated alkenes.
Scheme 7.34 Cu/Ph-BPE-mediated halogen migration–borylation.
Scheme 7.35 Copper/diphosphane-catalyzed aminoboration of oxa- and azabenzonorbornadienes.
Scheme 7.36 General mechanism of catalytic carbophilic activation.
Scheme 7.37 Synthesis of β-hydroxy-α-amino acids via aldol reaction between aldehydes and isocyanoacetate.
Scheme 7.38 1,3-Dipolar cycloaddition reaction with electron-deficient alkene in the presence of
C
2
-symmetric bis(phosphinegold(I) benzoate) catalysts.
Scheme 7.39 Bis(gold) catalyst for enantioselective cycloisomerizations of enynes.
Scheme 7.40 Formation of cation/carbenoid intermediates via gold-catalyzed cycloisomerization of 1,6-enynes.
Scheme 7.41 Ring-expanding cycloisomerization of 1,5-enynes containing cyclopropylidene moiety.
Scheme 7.42 Gold(I)-induced intermolecular cyclopropanation of styrenes.
Scheme 7.43 Desymmetrization of prochiral 1,4-dienes by an alkoxycyclization and subsequent enantioselective Claisen rearrangement.
Scheme 7.44 Bisphosphoramidite (AuCl)
2
/AgNTf
2
-catalyzed deracemization/intramolecular cyclopropanation of keto ester-derived racemic sulfur ylides.
Scheme 7.45 [2+2] and [4+2] cycloaddition reactions of eneallenes.
Scheme 7.46 Phosphoramidite (AuCl)/AgBF
4
enantioselective cycloisomerization.
Scheme 7.47 Kinetic asymmetric transformation of racemic pivalate ester to chromenyl pivalate in the presence of dinuclear gold–carbene complex.
Scheme 7.48 Gold-catalyzed hydroamination of allenes in the presence of a second chloride-ligated metal center.
Scheme 7.49 Cooperation between the chiral ligand and chiral anion, resulting in matched/mismatched pairs in the case of hydrocarboxylation reaction.
Scheme 7.50 Gold/(
R
)-
TRIP
(−)
-mediated cyclization of allenyl alcohols and allenyl sulfonamides.
Scheme 7.51 Enantioselective allylic alkylation of allyl alcohol in the synthesis of chiral vinyl chromane.
Scheme 7.52 Three-component, gold(I)-catalyzed coupling of aldimines, acetylene, and tosyl isocyanate.
Scheme 7.53 BINOL-phosphoric acid-catalyzed enantioselective hydroamination/
N
-sulfonyliminium cyclization cascade.
Scheme 7.54 Sakurai–Hosomi allylation of benzaldehyde with allyltrimethoxysilane.
Scheme 7.55 AgF and (
R
)-DIFLUORPHOS™-mediated reaction of acetophenone and allytrimethoxysilane.
Scheme 7.56 Cinchona alkaloid-derived aminophosphine and silver oxide catalytic system for asymmetric aldol reaction of isocyanoacetate and unactivated ketones.
Scheme 7.57 AgOAc-mediated Mannich reaction of siloxyfuran and ketoimine.
Scheme 7.58 Silver(I) hexafluorophosphate-catalyzed enantioselective propargylation of aryl and alkyl
N
-sulfonyl ketimines with allenyl pinacol borolane.
Scheme 7.59 Cycloaddition reaction between azomethine ylides and nitroalkenes in the presence of silver triflate or benzoate complexes with monodentate phosphoramidite ligand.
Scheme 7.60 Diastereoselective conjugate addition of azomethine ylide to nitroalkene.
Chapter 8: Chiral Rare Earth Lewis Acids
Scheme 8.1 Assessing the Lewis acidity by the tandem mass spectrometric method.
Figure 8.1 Lewis acidity (see Scheme 8.2) and six-coordinate ionic radii for the lanthanide series.
Scheme 8.2 Asymmetric Diels–Alder reaction catalyzed by Ytterbium–BINOL complex.
Scheme 8.3 Asymmetric 1,3-dipolar addition.
Scheme 8.4 Ytterbium-catalyzed Diels–Alder reaction.
Figure 8.2 Pybox ligands.
Figure 8.3 Structure of [La(OTf)
2
(Ph
4
-pybox)(H
2
O)
4
]
+
; view (a) perpendicular to plane of pybox (OTf
−
omitted for clarity) (b) parallel to plane of pybox.
Figure 8.4 Structure of [Sc(OTf)
3
(Inda-pybox)(H
2
O)]; view (a) perpendicular to plane of pybox (OTf
−
omitted for clarity) (b) parallel to plane of pybox.
Figure 8.6 Effect of Ln and pybox on enantioselectivity of Mukaiyama–Michael reaction [13, 22].
Figure 8.5 Proposed intermediate in Mukaiyama–Michael reaction.
Figure 8.7 Structures of (a) [La(OTf)
3
((
S
)-
i
Pr-pybox)
2
] and (b) [Yb(OTf)
2
((
R
)-
i
Pr-pybox)
2
][OTf].
Figure 8.8 Effect of Ln
3+
radius on selectivity of Ln(OTf)
3
/TIPSOCH
2
-pybox-catalyzed Diels–Alder reaction (see Table 8.1, entry 2).
Scheme 8.5 Application of chiral biquinoline
N
,
N
′-dioxide ligand for asymmetric Michael reaction.
Figure 8.9
C
2
-symmetric
N
,
N
′-dioxide ligands.
Figure 8.10 Structure of [Sc(OTf)(
L1a
)(H
2
O)]
2+
with coordinated OTf
−
(a) included and (b) omitted.
Scheme 8.6 Scandium-promoted asymmetric aldol reaction.
Scheme 8.7 Enantioselective addition of thioglycolate to chalcones in the presence of lanthanum triflate-based catalyst.
Scheme 8.8 Opposite enantioselectivities of Michael addition of pyrazolin-5-ones depended on the identity of Ln.
Scheme 8.9 Enantioselective aza-Diels–Alder reaction of butadiene with aldimines promoted by Sc(OTf)3 /L2a.
Scheme 8.10 Scandium-catalyzed Diels–Alder reaction reported by Fukazawa.
Scheme 8.11 The Mukaiyama aldol reaction of benzaldehyde.
Figure 8.11 Effect of Ln
3+
radius on selectivity in Ln(OTf)
3
/
L7
-catalyzed enantioselective Mukaiyama aldol reaction in aqueous medium.
Figure 8.12 Structure of [Ce(NO
3
)
2
L7
]
+
; view (a) perpendicular to Ce
L7
plane (NO
3
−
omitted for clarity) (b) along N–Ce–N direction.
Scheme 8.12 Nitroaldol reaction catalyzed by a cationic complex of Yb
3+
with a neutral donor-functionalized macrocyclic ligand.
Figure 8.13 Structure of acetate analog of proposed intermediate in Scheme 8.6.
Scheme 8.13 Binaphthol-derived chiral phosphonate as the catalyst for hetero-Diels–Alder reaction.
Scheme 8.14 Scandium tris(phosphonates)-catalyzed aza-Michael reaction of
O
-methylhydroxylamine with chalcones.
Figure 8.14 Mononuclear bifunctional catalysis.
Figure 8.15 Bimetallic catalysis.
Scheme 8.15 Reaction between lanthanides and bidentate ligands.
Scheme 8.16 Shibasaki’s enantioselective epoxidation reaction of α,β-unsaturated enones.
Figure 8.16 Dependence on Ln of isolated yield and
ee
for epoxidation reaction (Scheme 8.16).
Scheme 8.17 Aryloxy-functionalized prolinate ligand for ytterbium-catalyzed epoxidation of
trans
-chalcone.
Figure 8.17 Structure of [Yb(
L10
)
2
]
−
.
Scheme 8.18 Application of Gd
2
(
L11
)
3
for asymmetric cyanation of ketones.
Scheme 8.19 Gd
2
(
L11
)
3
-catalyzed enantioselective cyanation reactions of ketones and ketoimines, and ring opening of aziridines.
Scheme 8.20 Reaction between lanthanides and bidentate
N
,
N
-donor ligands.
Scheme 8.21 [Y(
L12)
{N(SiHMe
2
)
2
}]-promoted asymmetric ring opening of epoxides at low catalyst loadings.
Scheme 8.22 [Y(
L12)
{N(SiHMe
2
)
2
}]-promoted asymmetric ring opening of aziridines.
Scheme 8.23 Plausible catalytic cycle of [Y(
L12)
{N(SiHMe
2
)
2
}]-promoted asymmetric ring opening of aziridines.
Figure 8.18 View of the Y(
L12
) moiety taken from the structure of [Y(
L12
)(OH)]
2
.
Scheme 8.24 Enantioselective silylcyanation of benzaldehyde in the presence of Yb–pybox catalyst.
Figure 8.19 Two views of [YbCl
2
((
R
)-
i
Pr-pybox)
2
]
+
; (a) perpendicular to pybox plane (b) along
C
2
axis.
Scheme 8.25 Plausible catalytic cycle of LnCl
3
(
i
Pr-pybox)
2
-catalyzed silylcyanation of aldehydes.
Scheme 8.26 Enantioselective ring opening of epoxides in the presence of LnCl
3
∙6H
2
O/pybox catalyst.
Scheme 8.27 ErCl
3
∙6H
2
O/pybox-promoted cyanation of hydrazones.
Figure 8.20 Bifunctional M
3
[Ln(binol)
3
] catalyst.
Figure 8.21 Structures of (a) Li
3
[Y(
R
-binol)
3
] and (b) Li
3
[La(
R
-binol)
3
(THF)].
Scheme 8.28 Application of M
3
[Ln(binol)
3
] catalysts for various reactions.
Scheme 8.29 Mechanism of M
3
[Ln(binol)
3
]-promoted nitroaldol (Henry) reaction.
Scheme 8.30 The Michael addition of malonates to cyclic enones.
Scheme 8.31 Li
3
[Y(binol)
3
]-catalyzed aza-Michael reaction.
Scheme 8.32 Formation of the heterobimetallic catalyst [(
L13)
MLn(OAr)].
Scheme 8.33
syn
-Selective nitro-Mannich reaction in the presence of [(
L13
)Cu/Sm].
Scheme 8.34
anti
-Selective Pd/Sm-catalyzed nitroaldol reaction.
Chapter 9: Water-compatible Chiral Lewis Acids
Scheme 9.1 Yb(OTf)
3
-catalyzed Mukaiyama aldol reaction in aqueous media.
Scheme 9.2 First example of an asymmetric Mukaiyama aldol reaction in aqueous media.
Scheme 9.3 Chiral lead(II) catalyst for enantioselective Mukaiyama aldol reactions.
Scheme 9.4 Chiral praseodymium catalyst for enantioselective Mukaiyama aldol reactions.
Scheme 9.5 Chiral lanthanide catalysts for enantioselective Mukaiyama aldol reactions.
Scheme 9.6 (a) Praseodymium- and (b) silver-catalyzed asymmetric hydroxymethylation in aqueous media.
Scheme 9.7 Scandium-catalyzed asymmetric hydroxymethylation in aqueous media.
Scheme 9.8 Asymmetric Mukaiyama aldol reactions using formaldehyde in water.
Scheme 9.13 Chiral zinc(II) and iron(II) catalysts for asymmetric Mukaiyama aldol reactions.
Scheme 9.9 Bismuth-catalyzed asymmetric hydroxymethylation in aqueous media.
Scheme 9.10 Equilibrium between bismuth-2,2′-bipyridine
L5
complexes.
Scheme 9.11 Chiral gallium catalyst for enantioselective Mukaiyama aldol reactions.
Scheme 9.12 Chiral dendritic copper(II) catalyst for enantioselective Mukaiyama aldol reactions.
Scheme 9.14 Designed chiral iron(II) and zinc(II) catalysts.
Scheme 9.15 Optimal conditions for the iron(II)-catalyzed Mukaiyama aldol reaction.
Scheme 9.16 Chiral iron(II) catalyst for enantioselective Mukaiyama aldol reactions.
Scheme 9.17 Conditions for the Bi(III)-catalyzed Mukaiyama aldol reaction (Condition C).
Scheme 9.18 Metal-catalyzed aldol reaction.
Scheme 9.19 Accepted mechanism involving active site of class II FBP aldolases.
Scheme 9.20 Direct-type aldol reactions catalyzed by a zinc bis(proline) complex in aqueous media.
Scheme 9.21 Direct-type aldol reactions catalyzed by chiral zinc complexes in aqueous media.
Scheme 9.22 Direct-type aldol reactions catalyzed by various zinc complexes in aqueous media.
Scheme 9.23 Chiral ytterbium catalyst for direct aldol reaction in water.
Scheme 9.24 Design of a highly systemized catalytic system for asymmetric direct-type aldol reactions in 100% water.
Scheme 9.25 Asymmetric allylation reactions catalyzed by (
S
)-Tol-BINAP-silver(I) complex in aqueous media.
Scheme 9.26 Asymmetric allylation reactions catalyzed by chiral cadmium complex in aqueous media.
Scheme 9.27 Asymmetric allylation reactions catalyzed by chiral In(0) complex in water.
Scheme 9.28 Asymmetric allylation reactions catalyzed by a chiral zinc hydroxide complex in aqueous media.
Scheme 9.29 Asymmetric allylation reactions catalyzed by chiral silver oxide complex in water.
Scheme 9.30 Chiral Lewis acid for asymmetric reduction using aqueous borohydride.
Scheme 9.31 Asymmetric reduction of α-amino ketones with KBH
4
aqueous solution.
Figure 9.1 Coordination modes, selectivities, and isomerization of C═N bonds.
Scheme 9.32 Addition of enol ethers to hydrazones with Zn(II)–diamine catalysts.
Scheme 9.33 Enantioselective addition of terminal alkynes to imines in water.
Scheme 9.34 Enantioselective addition of terminal alkynes to imines in water using a tunable bis(imidazoline) ligand.
Scheme 9.35 Asymmetric allylation of hydrazonoester with allylboronate in aqueous media.
Scheme 9.36 Asymmetric Diels–Alder reaction in water.
Scheme 9.37 Solid-supported Cu(II)–DNA catalyst for an asymmetric Diels–Alder reaction.
Scheme 9.38 Rational design of Cu(II)–DNA catalyst for an asymmetric Diels–Alder reaction.
Scheme 9.39 Bio-inspired catalytic system consisting of Cu/phthalocyanine and BSA.
Scheme 9.40 Bio-inspired catalytic system consisting of a Cu/TAC scaffold.
Scheme 9.41 Asymmetric Kinugasa reaction in water.
Scheme 9.42 Asymmetric ring opening of
meso
-epoxide.
Scheme 9.43 Desymmetrization of
cis
-stilbene oxide with benzotriazole in water.
Scheme 9.44 Desymmetrization of
meso
-epoxides with indoles in water.
Scheme 9.45 The opposite sense of stereochemistry in asymmetric ring opening of
meso
-epoxides in water.
Scheme 9.46 Asymmetric conjugate addition of thiols in water.
Scheme 9.47 Asymmetric epoxidation of α,β-unsaturated ketones and amides using aqueous hydrogen peroxide.
Scheme 9.48 Ag(I)-catalyzed asymmetric Michael additions of β-ketoesters to nitroalkenes in water.
Scheme 9.49 Enantioselective conjugate addition of phenylacetylene to Meldrum’s acid-derived acceptors.
Scheme 9.50 Asymmetric Nazarov cyclization in water.
Scheme 9.51 Asymmetric Friedel–Crafts reaction catalyzed by Cu(II)/dmbpy/DNA catalysts.
Scheme 9.52 Asymmetric Michael addition catalyzed by Cu(II)/dmbpy/DNA catalysts.
Scheme 9.53 Asymmetric Michael addition catalyzed by chiral ytterbium catalysts.
Scheme 9.54 Asymmetric C─H functionalization of indole in water.
Scheme 9.55 Asymmetric boron conjugate addition catalyzed by copper(II) catalysts.
Scheme 9.56 Asymmetric silyl conjugate addition catalyzed by heterogeneous copper(II) catalysts in water.
Scheme 9.57 Tandem 1,4-addition/enantioselective protonation in water.
Chapter 10: Cooperative Lewis Acids and Aminocatalysis
Scheme 10.1 Examples of multicatalysis.
Scheme 10.2 Dual activation
via
metal activation catalysis and aminocatalysis.
Scheme 10.3 Cooperative dual catalysis by combining amine and transition-metal catalysts.
Scheme 10.4 The proposed catalytic cycle for the direct enantioselective intermolecular α-allylic alkylation of aldehydes.
Scheme 10.5 Direct intramolecular α-allylic alkylation of aldehydes.
Scheme 10.6 Direct α-allylic alkylation of α-branched aldehydes.
Scheme 10.7 Proposed mechanism for the direct α-allylic alkylation of α-branched aldehydes.
Scheme 10.8 Enantioselective dynamic cascade reaction for the synthesis of polysubstituted carbocycles.
Scheme 10.9 α-Allylic alkylation with allylic alcohols.
Scheme 10.10 Enantioselective α-allylic alkylation employing allylic alcohols.
Scheme 10.11 Enantioselective α-allylic alkylation with allylic alcohols by combined enamine and transition metal catalysis.
Scheme 10.12 Stereodivergent control of the α-allylic alkylation with allylic alcohols and α-branched aldehydes.
Scheme 10.13 α-Allylic alkylation of terminal alkenes with aldehydes or ketones.
Scheme 10.14 Direct α-allylic alkylation of alkynes with aldehydes or ketones.
Scheme 10.15 A combination of Lewis acid and aminocatalysts for the multicomponent reaction.
Scheme 10.16 A combination of Lewis acid and aminocatalysts for the synthesis of carbocycles.
Scheme 10.17 A combination of indium salt and aminocatalyst for the synthesis of carbocycles.
Scheme 10.18 Cooperative catalysis for the one-pot enantioselective Michael addition cyclization reaction.
Scheme 10.19 Asymmetric cross-aldol reaction of ynals by a multicatalytic system.
Scheme 10.20 Merging rhodium and aminocatalysts in the α-alkenylation of ketones and alkynes.
Scheme 10.21 Proposed reaction mechanism for the α-alkenylation of ketones and alkynes.
Scheme 10.22 Lewis acid catalysis combined with iminium and enamine activation catalysis.
Scheme 10.23 Dynamic kinetic asymmetric transformation by combined amine- and transition-metal-catalyzed enantioselective cycloisomerization.
Scheme 10.24 Proposed reaction mechanism for the Pd(II)-catalyzed carbocyclization.
Scheme 10.25 Cooperative catalysis for the stereoselective synthesis of spirocyclopentene oxindoles.
Scheme 10.26 Enantioselective propargylic alkylation of aldehydes with propargylic alcohols.
Scheme 10.27 The synergistic catalyzed reaction for the α-vinylidenation of aldehydes.
Scheme 10.28 Combined oxidation and dual cooperative catalysis for the one-pot synthesis of 3-acylpyrroles.
Scheme 10.29 Intramolecular carbocyclization between carbonyl compounds and allenes.
Scheme 10.30 Metal and amine co-catalyzed carbocyclization of cinnamic aldehyde with allenes.
Scheme 10.31 Catalytic enantioselective α-alkenylation of aldehydes.
Scheme 10.32 Lewis acid activation of alcohol substrates in combination with enamine activation catalysis in the α-alkylation of aldehydes.
Scheme 10.33 Combination of Lewis acid activation catalysis and enamine activation catalysis in the enantioselective aldol reactions.
Scheme 10.34 Catalytic enantioselective inverse-electron-demand Diels–Alder reaction.
Scheme 10.35 Dual cooperative catalysis for the catalytic enantioselective silylation of α,β-unsaturated aldehydes.
Scheme 10.36 Catalytic enantioselective addition of alkylbenzoxazoles to enals by dual activation catalysis.
Scheme 10.37 Copper and iminium catalysis for the synthesis of pyridines.
Scheme 10.38 A combination of Lewis acid and aminocatalyst for the enantioselective synthesis of cyclohexenones.
List of Tables
Chapter 1: Alkaline-Earth Metal-Based Chiral Lewis Acids
Table 1.1 Asymmetric [3+2] cycloaddition of a glycine ester Schiff base with α,β-unsaturated carbonyl compounds [1].
Table 1.2 Asymmetric [3+2] cycloaddition of a Schiff base of a glycine ester with
t
-butyl crotonate [1].
Table 1.3 Asymmetric [3+2] cycloaddition of a Schiff base of α-amino esters with α,β-unsaturated carbonyl compounds [1].
Table 1.4 Influence of the alkaline earth metal complexes on the enantio- and diastereoselectivity of the asymmetric Diels–Alder reaction.
Table 1.5 Chiral alkaline earth metal complex-catalyzed catalytic Mannich reactions of sulfonylimidates with
N
-Boc-imines.
Table 1.6 Catalytic asymmetric Mannich reactions of α-isothiocyanate esters with ketimines.
Table 1.7 Chiral barium aryloxide-catalyzed Mannich reactions of β,γ-unsaturated esters with imines.
Table 1.8 Chiral calcium phosphate-catalyzed asymmetric Mannich reactions.
Table 1.9 Chiral calcium phosphate-catalyzed asymmetric Mannich reaction of
N
-Boc-imine with pyrone.
Table 1.10 Chiral calcium phosphate-catalyzed asymmetric Mannich reaction of
N
-Boc-imine with 1,3-cyclohexadione.
Table 1.11 Asymmetric Mannich reactions of malonates with
N
-Boc imines catalyzed by a chiral PyBox–calcium complex.
Chapter 2: Titanium-Based Chiral Lewis Acids
Table 2.1 Asymmetric ring-opening reaction of oxides with aromatic amines.
Table 2.2 Asymmetric ring opening of
meso
-epoxides with aryl selenols and thiols in the presence of Ga–Ti–salen catalyst.
Chapter 5: Zinc-based Chiral Lewis Acids
Table 5.1 Various zinc-based catalytic systems for the asymmetric hydrosilylation of acetophenone.
Chapter 6: From Noble Metals to Fe-, Co-, and Ni-based Catalysts: A Case Study of Asymmetric Reductions
Table 6.1 Some important catalytic reactions employed in industry.
Table 6.2 Asymmetric hydrosilylation of acetophenone using Cu─H and various chiral ligands.
Table 6.3 Asymmetric hydrosilylation of acetophenone using Cu(OAc)
2
∙H
2
O and various chiral ligands.
Chapter 8: Chiral Rare Earth Lewis Acids
Table 8.1 Reactions catalyzed by Ln(OTf)
3
/pybox (see Figure 8.2 for pybox structures).
Table 8.2 Optimized conditions for enantioselective catalysis of Mukaiyama aldol reaction in aqueous media.
Chapter 9: Water-compatible Chiral Lewis Acids
Table 1.1 Hydrolysis constants and exchange rate constants for substitution of inner-sphere water ligands [4].
Table 9.2 Effect of Yb salts and correlation between product stereochemistry and amount of water.
Chiral Lewis Acids in Organic Synthesis
Edited by
Jacek Mlynarski
Editor
Prof. Jacek Mlynarski
Jagiellonian University
Faculty of Chemistry
Ingardena 3
30-060 Krakow
Poland
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List of Contributors
Samson Afewerki
Mid Sweden University
Department of Natural Sciences
SE-851 70 Sundsvall
Sweden
Helen C. Aspinall
University of Liverpool
Department of Chemistry
Crown Street
Liverpool L69 7ZD
UK
Sebastian Baś
Jagiellonian University
Ingardena 3
30-060 Krakow
Poland
Armando Córdova
Mid Sweden University
Department of Natural Sciences
SE-851 70 Sundsvall
Sweden
Anna Domżalska
Institute of Organic Chemistry
Polish Academy of Sciences
Warsaw
Poland
Xiaoming Feng
College of ChemistrySichuan University
Key Laboratory of Green Chemistry & Technology, Ministry of Education
Chengdu
China
Bartłomiej Furman
Institute of Organic Chemistry
Polish Academy of Sciences
Warsaw
Poland
Jadwiga Gajewy
Adam Mickiewicz UniversityDepartment of ChemistryUmultowska 89B61 614 Poznan
Poland
I. Karthikeyan
North Dakota State University
Department of Chemistry and Biochemistry
Dunbar Hall 354, 1231 Albrecht Blvd.
Fargo, ND 58108-6050
USA
Taku Kitanosono
The University of Tokyo
Department of ChemistrySchool of Science
Hongo, Bunkyo-ku
Tokyo 113-0033
Japan
Shu Kobayashi
The University of Tokyo
Department of ChemistrySchool of Science
Hongo, Bunkyo-ku
Tokyo 113-0033
Japan
Marcin Kwit
Adam Mickiewicz UniversityDepartment of ChemistryUmultowska 89B61 614 Poznan
Poland
Daniel Łowicki
Adam Mickiewicz UniversityDepartment of ChemistryUmultowska 89B61 614 Poznan
Poland
Jacek Mlynarski
Jagiellonian University
Faculty of Chemistry
Ingardena 3
30-060 Krakow
Poland
Thierry Ollevier
Université Laval
Département de Chimié
Pavillon Alexandre-Vachon 1045 avenue de la Médecine
Québec
Canada G1V 0A6
Radovan Šebesta
Comenius University
Department of Organic Chemistry
Mlynska dolina, Ilkovicova 6
84215 Bratislava
Slovakia
Mukund P. Sibi
North Dakota State University
Department of Chemistry and Biochemistry
Dunbar Hall 354, 1231 Albrecht Blvd.
Fargo, ND 58108-6050
USA
Marcin Szewczyk
Jagiellonian University
Ingardena 3
30-060 Krakow
Poland
Artur Ulikowski
Institute of Organic Chemistry
Polish Academy of Sciences
Warsaw
Poland
Jun Wang
School of ChemistrySun Yat-Sen UniversityXingang West Road 135
Guangzhou 510275
P. R. China
Matej Žabka
Comenius University
Department of Organic Chemistry
Mlynska dolina, Ilkovicova 6
84215 Bratislava
Slovakia
Preface
Metal catalysis still lies at the heart of modern chemistry. Application of chiral metal complexes for asymmetric synthesis has become a key activity for organic chemists in the past 20–30 years. Particularly, the second half of the twentieth century documented vast progress in the development of transition metal-based asymmetric synthesis. The Nobel Prize was awarded for this tremendous effort in 2001 to William S. Knowles and Ryoji Noyori ‘‘for their work on chirally catalysed hydrogenation reactions’’ and to K. Barry Sharpless ‘‘for his work on chirally catalysed oxidation reactions.’’ On the other hand, enantioselective organocatalysis has recently become a field of central importance for the asymmetric synthesis of chiral molecules. Since the ground-breaking work of, for example, B. List and D. W. C. MacMillan in the early 2000s, this field has grown at an extraordinary pace from a small collection of reactions to a flourishing area of transformations. The use of metal complexes, however, never ceased to be an important area of research. Parallel to the organocatalysis, application of chiral Lewis acids is still the most important field of research. Moreover, there are many important classes of synthetic transformations for which application of chiral metal-based Lewis acids are essential.
Now, after many years of academic endeavor the stereocontrol in organic synthesis has become also a major issue for the chemical industry. The basic criteria for such applications, efficiency, economy, and ecology are equally well met by purely organic molecules as well as by asymmetric metal-based reagents. In fact, many transformations have been discovered or recently reinvented under asymmetric control by using chiral Lewis acids while industrial application of organocatalysis is still at an early stage.
This book was thought of as a panorama of modern chiral Lewis acid-type catalysts and their broad applications. We tried to emphasize the most recent contributions in the field as well as more prominent directions of development. The first chapters venture into various parts of the periodic table, giving insight into extensive application of alkaline metals, as well as classical Lewis acids such as titanium, iron, copper, and zinc. Recently prepared chiral alkaline earth metal complexes (calcium, strontium, and barium) showed that their strong Brønsted basicity and mild Lewis acidity are useful for construction of chiral catalysts for various carbon–carbon bond forming reactions (Chapter 1). Alkaline earth metal catalysis is undoubtedly also an important topic from the viewpoint of green sustainable chemistry. The next chapters demonstrate broad application and growing interest in some of the most abundant metals on Earth: titanium (Chapter 2) and iron (Chapter 3). The major advantages of titanium chemistry are the possibility of adjusting reactivity and selectivity by ligands and the relative inertness toward redox processes. Iron salts, on the other hand, are cheap, less harmful, and benign. Chapters 4 and 5 detail the broad utility and application of copper- and zinc-based Lewis acids in organic transformations for the synthesis of important classes of compounds. Chapter 6 deals with growing interest in non-noble metal catalysts useful for asymmetric reduction, while Chapter 7 provides insight into coinage metals copper, silver, and gold, which can be considered as prominent examples of carbophilic Lewis acids. Such compounds displaying affinity towards carbon–carbon double or triple bonds are important in a wide range of chemical reactions. The last three chapters provide information on recent hot topics in the area: application of chiral lanthanide complexes (Chapter 8), water-compatible Lewis acids (Chapter 9), and cooperative application of chiral metal complexes and aminocatalysis (Chapter 10).
All chapters are thoroughly well written by experts in the respective fields. It is my personal pleasure to express gratitude to all contributors to this book for their effort to join this editorial enterprise. I am also grateful to the Wiley-VCH team who made this project real.
Jacek MlynarskiKrakow 2016
Chapter 1Alkaline-Earth Metal-Based Chiral Lewis Acids
Anna Domżalska, Artur Ulikowski and Bartłomiej Furman
Institute of Organic Chemistry, Polish Academy of Sciences, Warsaw, Poland
1.1 Introduction
Catalysis based on transition metal compounds has received considerable attention over the years. In this field, asymmetric catalysis based on chiral Lewis acids is broadly recognized as a significant tool for the preparation of optically active compounds. However, from the perspective of green sustainable chemistry, it is highly preferred to find environmentally friendly processes and catalysts. In contrast to most transition and noble metal complexes, chiral alkaline-earth metal-based catalysts offer high efficiency and stereoselectivity but also less toxicity and less potential for harm. That is why the studies of asymmetric transformations with the use of these novel catalytic systems are attracting ever-growing interest.
1.2 General Properties of Alkaline Earth Metal Compounds
In alkaline-earth metal-catalyzed reactions, the amphoteric acid/base character of the complexes is of extreme importance. The strong Brønsted basicity allows for the abstraction of acidic protons, such as the α-protons of carbonyl compounds. On the other hand, the significant Lewis acidity is used for stereocontrol of the reaction [1–5]. These unique properties of alkaline earth metal complexes are due to the chemical properties of Group II metals. Both the Brønsted basicity and the Lewis acidity are directly connected to the electronegativity of the metals [1, 2, 5]. For this reason, the calcium compounds are weaker Brønsted bases and stronger Lewis acids than barium and strontium complexes when coupled with similar counterions [1, 2, 5]. However, the smaller ionic radius and smaller coordination number of calcium makes it more amenable to chiral modifications than strontium or barium [1, 4, 6]. Moreover, the character of the ligand exerts an influence not only on the asymmetric environment construction but also on the amphoteric acid/base character of the alkaline earth metal compounds. Taking into account the character of ligands and the type of bonds between the metal and the ligand, chiral alkaline earth metal complexes have been classified into three types (Figure 1.1) [1, 2, 5].
Figure 1.1 Types of alkaline earth metal complexes.
In the first type of complexes, the metal is tightly connected to the anionic chiral ligands through covalent bonds. Since these ligands act as Brønsted bases, it is difficult to control the basicity of the catalyst. However, when anionic chiral ligands are bonded to the metal by a combination of one covalent and further coordinative bonds (type II), the Brønsted basicity can be controlled by changing the remaining free counterion [1, 2, 5]. Thanks to the presence of a covalent bond in both type I and type II complexes, there is a possibility for strict control of the asymmetric environment [1, 2, 5].
