Iodine Catalysis in Organic Synthesis E-Book

• Herausgeber: Wiley-VCH GmbH
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch

Seitenzahl: 659

Veröffentlichungsjahr: 2022

Beschreibung

Iodine Catalysis in Organic Synthesis

The first book of its kind to highlight iodine as a sustainable alternative to conventional transition metal catalysis

Iodine Catalysis in Organic Synthesis provides detailed coverage of recent advances in iodine chemistry and catalysis, focusing on the utilization of various iodine-containing compounds as oxidative catalysts. Featuring contributions by an international panel of leading research chemists, this authoritative volume explores the development of environmentally benign organic reactions and summarizes catalytic transformations of molecular iodine and iodine compounds such as hypervalent organoiodine and inorganic iodine salts.

Readers are first introduced to the history of iodine chemistry, the conceptual background of homogeneous catalysis, and the benefits of iodine catalysis in comparison with transition metals. Next, chapters organized by reaction type examine enantioselective transformations, catalytic reactions involving iodine, catalyst states, oxidation in iodine and iodine catalyses, and catalytic reactions based on halogen bonding. Practical case studies and real-world examples of different applications in organic synthesis and industry are incorporated throughout the text. An invaluable guide for synthetic chemists in both academic and industrial laboratories, Iodine Catalysis in Organic Synthesis:

• Provides a thorough overview of typical iodine-catalyzed reactions, catalyst systems, structures, and reactivity
• Explores promising industrial applications of iodine-based reagents for organic synthesis
• Highlights the advantages iodine catalysis has over classical metal-catalyzed reactions
• Discusses sustainable and eco-friendly methods in hypervalent iodine chemistry

Edited by two world authorities on the catalytic applications of organoiodine compounds, Iodine Catalysis in Organic Synthesis is required reading for catalytic, organic, and organometallic chemists, medicinal and pharmaceutical chemists, industrial chemists, and academic researchers and advanced students in relevant fields.

Leseprobe

Table of Contents

Cover

Title Page

Copyright

Preface

1 Historical Introduction

1.1 Discovery of Iodine and Early Studies

1.2 Iodine Research in the Twentieth Century

1.3 Iodine Research in the Twenty‐first Century

1.4 Brief History of Iodine Catalysis

References

2 Concepts in Iodine Catalysis

2.1 Introduction

2.2 Halogen‐bonding Catalysis

2.3 Iodine(I) Catalysis

2.4 Iodine(III) Catalysis

2.5 Iodine(V) Catalysis

References

3 Catalysis by Halogen Bonding Based on Iodine

3.1 Introduction

3.2 Catalysis by Molecular Iodine

3.3 Catalysis by Organic Halogen Bond Donors

3.4 Asymmetric Catalysis Through Halogen Bonding

3.5 Halogen Bonding as Supporting Interaction in Catalysis

3.6 Conclusion

References

4 Catalytic Transformations with R

4

NI Catalyst Precursors

4.1 Introduction

4.2 The Construction of C–N Bond

4.3 The Construction of C–O Bond

4.4 The Construction of C–C Bond

4.5 The Construction of C–S Bond

4.6 Cascade Bond Formation

4.7 The Formation of P–O/C, S–N Bond

4.8 Conclusion

References

5 Catalytic Transformations Based on Iodine(I) Involving Radical Pathways

5.1 Introduction

5.2 Synthesis of Iodine(I) Complexes

5.3 Reactivity

5.4 Application in Catalysis

5.5 Conclusions

References

6 Aromatic C–H Functionalization

6.1 Introduction

6.2 Reactions with Stoichiometric Hypervalent Iodine Reagents

6.3 Hypervalent Iodine‐Catalyzed C–H Functionalization Reactions

6.4 Conclusion

References

7 Design of Chiral Organoiodine(I/III) Catalysts for Asymmetric Oxidative Transformations

7.1 Introduction

7.2 C1‐Symmetric Iodoarenes

7.3 C2‐Symmetric Catalysts

7.4 Comparison of Catalyst Performance

7.5 Conclusion

References

8 Catalytic and Asymmetric Dearomatization Reactions Employing Hypervalent Iodine Reagents

8.1 Introduction: Phenol Dearomatization

8.2 Asymmetric Dearomative Coupling: A Turning Point

8.3 Catalytic Asymmetric Dearomative Couplings

8.4 Further Breakthrough and Recent Advances

8.5 Essential Mechanistic Guide

8.6 Summary

References

9 Catalytic Alkene Difunctionalization Reactions

9.1 Introduction

9.2 General Mechanistic Considerations

9.3 Oxyfunctionalization

9.4 Aminofunctionalization

9.5 Dihalogenation

9.6 Carbofunctionalization

9.7 Conclusion and Outlook

References

10 Catalytic Oxidative α‐Functionalization of Carbonyls

10.1 Introduction

10.2 Organoiodine(III) Catalysis

10.3 Inorganic Iodine Catalysis

10.4 Conclusion

References

11 Oxidations with Iodine(V) Compounds – From Stoichiometric Compounds to Catalysts

11.1 Introduction to Iodine(V) Compounds

11.2 Iodine(V) Compounds as Stoichiometric Reagents in Organic Syntheses

11.3 Iodine(V) Compounds as Recyclable Reagents in Organic Syntheses

11.4 Iodine(V) Compounds as Catalytic Reagents in Organic Syntheses

11.5 Conclusion

References

12 Sustainable Methods in Hypervalent Iodine Chemistry

12.1 Introduction

12.2 Chemical Synthesis of Hypervalent Iodine Reagents

12.3 Electrochemical Synthesis of Hypervalent Iodine Reagents

12.4 Recyclable Hypervalent Iodine Reagents

12.5 Catalytic Application of Hypervalent Iodine Compounds

12.6 Conclusion

Acknowledgment

References

Note

13 Industrial Application of Iodine Catalysis

13.1 Synthetic Acetic Acid

13.2 Tall Oil

13.3 Photoinitiator

13.4 Polymerization (Chain Transfer Agent, Initiator, and Catalyst)

13.5 Dye‐Sensitized Solar Cell (DSSC)

13.6 Polyamide Stabilizer

References

Index

End User License Agreement

List of Tables

Chapter 7

Table 7.1 General synthetic routes to

C

1

‐symmetric chiral iodoarenes.

Table 7.2 General synthetic routes to

C

2

‐symmetric chiral iodoarenes.

Chapter 12

Table 12.1 List of general oxidants in order of their respective active oxyg...

Chapter 13

Table 13.1 Disproportionation of Rosin

a)

.

Table 13.2 Main commercially available fluoroelastomers.

Table 13.3 Comparison of different polymer stabilizer systems.

Table 13.4 Effects of stabilizer systems on LTTS of polyamide 6

a)

at differe...

List of Illustrations

Chapter 1

Figure 1.1 First examples of polyvalent organoiodine compounds reported in 1...

Scheme 1.1 Catalytic oxidative spirocyclization reaction of a phenolic subst...

Scheme 1.2 Catalytic α‐acetoxylation of carbonyl compounds in the presence o...

Chapter 2

Scheme 2.1 Iodine compounds.

Scheme 2.2 Production of acetic acid by the Cativa process.

Scheme 2.3 (a) Iodine‐catalyzed coupling reaction. (b) Transition‐metal‐cata...

Scheme 2.4 Activation of molecular iodine through double halogen‐bonding int...

Scheme 2.5 General catalytic cycle of hypoiodite catalysis for oxidative cou...

Scheme 2.6 Hypoiodite‐catalyzed tandem oxidative cyclization/coupling reacti...

Scheme 2.7 Hypoiodite‐catalyzed tandem oxidative cyclization/epoxidation rea...

Scheme 2.8 Hypoiodite‐catalyzed tandem oxidative cyclization/epoxidation rea...

Scheme 2.9 Iodine‐catalyzed generation of alkoxy and alkylperoxy radicals.

Scheme 2.10 General catalytic cycle of organoiodine(III) catalysis for oxida...

Scheme 2.11 Enantioselective Kita oxidative spirolactonization reactions.

Scheme 2.12 General catalytic cycle of organoiodine(III) catalysis for alken...

Scheme 2.13 Catalytic enantioselective diacetyoxylation of styrenes reported...

Scheme 2.14 Aerobic oxidation protocols from iodoarenes to organoiodine(III)...

Scheme 2.15 Photoinduced aerobic iodoarene catalysis for spirocyclization.

Scheme 2.16 Synthetic approach toward 4‐(dimethylamino)pyriidine (DMAP) usin...

Scheme 2.17 IBS‐catalyzed oxidation of alcohols and arenols. (a)

In situ

pre...

Scheme 2.18 Proposed aerobic catalytic cycle of I(V) species.

Chapter 3

Scheme 3.1 Iodine‐catalyzed reactions. (a) Dehydration of alcohols, (b) Diel...

Scheme 3.2 Iodine‐catalyzed additions of silyl nucleophiles. (a) Mukaiyama‐a...

Scheme 3.3 Iodine‐catalyzed cyclizations through halogen bonding. (a) Prins ...

Figure 3.1 General representation of halogen‐bonding catalysis.

Figure 3.2 Cationic XB donors.

Figure 3.3 Neutral multidentate XB donors.

Scheme 3.4 Transient (top a, b) and non‐transient (bottom c, d) XB in organi...

Scheme 3.5 Enantioselective halocyclization reactions involving halogen bond...

Scheme 3.6 XB‐induced halide abstraction reactions. (a) Ritter‐type reaction...

Figure 3.4 Iodine (III)‐derived XB donors.

Scheme 3.7 Reactions involving XB‐catalyzed halide abstraction. (a) Halide a...

Scheme 3.8 XB‐mediated polymerizations. (a) Neutral group activation, (b) Ha...

Figure 3.5 Activation of organic functional groups through halogen bonding....

Scheme 3.9 XB activation of

N

‐based Lewis basic functional groups in organic...

Scheme 3.10 XB‐catalyzed reactions of conjugated carbonyl compounds. (a) Die...

Scheme 3.11 XB‐induced 1,2‐additions to carbonyl derivatives. (a) Friedel Cr...

Scheme 3.12 Glycosylation through XB interaction. (a) Multistage strain‐rele...

Scheme 3.13 Bromocarbocyclization via halogen bonding.

Scheme 3.14 Umpolung C–C bond formation involving an iodolium ylide‐halogen ...

Scheme 3.15 Halogen‐bonding‐catalyzed nitro‐Michael addition.

Scheme 3.16 Catalysis by XB‐induced π‐activation. (a) [4+2] Cycloaddition, (...

Figure 3.6 Triazolium‐based chiral XB donors.

Scheme 3.17 A bis(imidazolium)‐based bidentate chiral XB donor in asymmetric...

Scheme 3.18 Chirality transfer by pentanidium salts. (a) Alkylation of sulfi...

Scheme 3.19 Neutral XB‐catalyzed enantioselective reactions. (a) Michael/Hen...

Figure 3.7 Stabilization of reaction precursors through XB.

Scheme 3.20 XB‐assembled bidentate phosphine‐complexed Rh(I) catalyst.

Scheme 3.21 XB template‐induced macrocyclization.

Scheme 3.22 Thiourea/XB donor co‐catalysis for direct

N

‐glycofunctionalizati...

Scheme 3.23 XB‐induced cleavage of an Au‐Cl bond to generate an activated me...

Chapter 4

Scheme 4.1

n

‐Bu

4

NI‐catalyzed synthesis of

α

‐ketoamides from aryl methyl...

Scheme 4.2

n

‐Bu

4

NI‐catalyzed synthesis of

α

‐ketoamides from ethylarenes...

Scheme 4.3

n

‐Bu

4

NI‐catalyzed synthesis of isatins from 2′‐aminoacetophenones...

Scheme 4.4

n

‐Bu

4

NI‐catalyzed synthesis of amides from aldehydes and tertiary...

Scheme 4.5

n

‐Bu

4

NI‐catalyzed synthesis of amides from aldehydes and formamid...

Scheme 4.6

n

‐Bu

4

NI‐catalyzed synthesis of amides from benzyl alcohols and am...

Scheme 4.7 Et

4

NI‐catalyzed synthesis of primary amides from benzylic aldehyd...

Scheme 4.8

n

‐Bu

4

NI‐catalyzed synthesis of arylcarboxyamides from acyl peroxi...

Scheme 4.9

n

‐Bu

4

NI‐catalyzed synthesis of hemiaminal ether framework from al...

Scheme 4.10

n

‐Bu

4

NI‐catalyzed synthesis of hemiaminal ether skeletons from a...

Scheme 4.11

n

‐Bu

4

NI‐catalyzed synthesis of hemiaminal ethers from ethers and...

Scheme 4.12

n

‐Bu

4

NI‐catalyzed synthesis of 9‐alkylated purine derivatives fr...

Scheme 4.13

n

‐Bu

4

NI‐catalyzed synthesis of alkylated aryl tetrazoles from me...

Scheme 4.14

n

‐Bu

4

NI‐catalyzed synthesis of 2‐alkylated tetrazoles from tetra...

Scheme 4.15

n

‐Bu

4

NI‐catalyzed synthesis of aminonitrile 2‐aminobenzoxazole d...

Scheme 4.16

n

‐Bu

4

NI‐catalyzed synthesis of

N

‐substituted anilines from anili...

Scheme 4.17

n

‐Bu

4

NI‐catalyzed synthesis of aminonitrile from cyanoacetic aci...

Scheme 4.18

n

‐Bu

4

NI‐catalyzed synthesis of 3,2′‐pyrrolidinyln spirooxindoles...

Scheme 4.19

n

‐Bu

4

NI‐catalyzed synthesis of tertiary azides from 1,3‐dicarbon...

Scheme 4.20

n

‐Bu

4

NI‐catalyzed synthesis of aziridines from styrenes.

Scheme 4.21

n

‐Bu

4

NI‐catalyzed synthesis of aziridines from alkenes and

N

‐ami...

Scheme 4.22

n

‐Bu

4

NI‐catalyzed synthesis of azaspirocyclohexadienones from (

N

Scheme 4.23

n

‐Bu

4

NI‐catalyzed synthesis of functionalized azetidines from am...

Scheme 4.24

n

‐Bu

4

NI‐catalyzed C–O bond formation

via

alkylarenes.

Scheme 4.25

n

‐Bu

4

NI‐catalyzed synthesis of Δ

2

‐isoxazolines from oximes.

Scheme 4.26

n

‐Bu

4

NI‐catalyzed synthesis of

α

‐acyloxy ketones from keton...

Scheme 4.27

n

‐Bu

4

NI‐catalyzed synthesis of lactones from aliphatic carboxyli...

Scheme 4.28

n

‐Bu

4

NI‐catalyzed synthesis of peroxides from esters.

Scheme 4.29

n

‐Bu

4

NI‐catalyzed

α

‐aminoxylation of ketones from ketones a...

Scheme 4.30

n

‐Bu

4

NI‐catalyzed synthesis of

α

‐acyloxy ethers from carbox...

Scheme 4.31

n

‐Bu

4

NI‐catalyzed synthesis of

N

‐acyloxymethylamides and

α

‐...

Scheme 4.32

n

‐Bu

4

NI‐catalyzed synthesis of deoxygenation products from carbo...

Scheme 4.33

n

‐Bu

4

NI‐catalyzed synthesis of 3‐acyloxy‐2,3‐dihydrobenzofurans ...

Scheme 4.34

n

‐Bu

4

NI‐catalyzed synthesis of

tert

‐butyl peresters and allylic ...

Scheme 4.35

n

‐Bu

4

NI‐catalyzed synthesis of esters from aldehydes and alkyl h...

Scheme 4.36

n

‐Bu

4

NI‐catalyzed synthesis of aryl esters from benzylic primary...

Scheme 4.37

n

‐Bu

4

NI‐catalyzed synthesis of carboxylic esters from

N

‐alkoxyam...

Scheme 4.38

n

‐Bu

4

NI‐catalyzed synthesis of 2‐acyl‐2,3‐dihydrobenzofuran deri...

Scheme 4.39

n

‐Bu

4

NI‐catalyzed synthesis of functionalized diacetoxylation pr...

Scheme 4.40

n

‐Bu

4

NI‐catalyzed synthesis of cyclic carbonates from epoxides a...

Scheme 4.41

n

‐Bu

4

NI‐catalyzed synthesis of functionalized [6.6.5] tricyclic ...

Scheme 4.42

n

‐Bu

4

NI‐catalyzed synthesis of methylene‐bridged bis‐1,3‐dicarbo...

Scheme 4.43

n

‐Bu

4

NI‐catalyzed synthesis of diaryl ketones from stilbenes.

Scheme 4.44

n

‐Bu

4

NI‐catalyzed synthesis of 1,3‐diketones from aldehydes and ...

Scheme 4.45

n

‐Bu

4

NI‐catalyzed synthesis of phenanthridines and quinoxalin‐2‐...

Scheme 4.46

n

‐Bu

4

NI‐catalyzed synthesis of enaminones from

α

‐keto acids...

Scheme 4.47

n

‐Bu

4

NI‐catalyzed synthesis of cyclopropanes from iodonium ylide...

Scheme 4.48

n

‐Bu

4

NI‐catalyzed synthesis of alkylated BODIPYs from BODIPYs an...

Scheme 4.49

n

‐Bu

4

NI‐catalyzed synthesis of 4

H

‐chromen‐4‐ones from chroman‐4‐...

Scheme 4.50

n

‐Bu

4

NI‐catalyzed synthesis of allylic sulfones from sulfonyl hy...

Scheme 4.51

n

‐Bu

4

NI‐catalyzed synthesis of

β

‐carbonyl sulfones from sul...

Scheme 4.52

n

‐Bu

4

NI‐catalyzed synthesis of 3‐sulfenylindoles from indoles an...

Scheme 4.53

n

‐Bu

4

NI‐catalyzed synthesis of difluoromethylthiolated aromatics...

Scheme 4.54

n

‐Bu

4

NI‐catalyzed synthesis of benzimidazole derivatives from di...

Scheme 4.55

n

‐Bu

4

NI‐catalyzed synthesis of imidazo[1,2‐

a

]pyridines from 2‐am...

Scheme 4.56

n

‐Bu

4

NI‐catalyzed synthesis of imidazo[1,2‐

a

]pyridines from amin...

Scheme 4.57

n

‐Bu

4

NI‐catalyzed synthesis of imidazo[1,5‐

c

]‐quinazolines from ...

Scheme 4.58

n

‐Bu

4

NI‐catalyzed synthesis of isoxazoline functionalized phenan...

Scheme 4.59

n

‐Bu

4

NI‐catalyzed synthesis of isoxazoline‐functionalized isoqui...

Scheme 4.60

n

‐Bu

4

NI‐catalyzed synthesis of aminooxylated oxindoles from alke...

Scheme 4.61

n

‐Bu

4

NI‐catalyzed synthesis of 2‐aminobenzofuran‐3(2

H

)‐ones from...

Scheme 4.62

n

‐Bu

4

NI‐catalyzed synthesis of 3‐methoxyindolines and 3‐ethoxyin...

Scheme 4.63

n

‐Bu

4

NI‐catalyzed synthesis of oxazolidinone derivatives from CO

Scheme 4.64

n

‐Bu

4

NI‐catalyzed synthesis of 2‐aminobenzothiazoles from aryl i...

Scheme 4.65

n

‐Bu

4

NI‐catalyzed synthesis of 1,2,4‐thiadiazoles and pyrido‐fus...

Scheme 4.66

n

‐Bu

4

NI‐catalyzed synthesis of substituted pyrrolin‐4‐ones from ...

Scheme 4.67

n

‐Bu

4

NI‐catalyzed synthesis of quinazolinones from 3‐methylindol...

Scheme 4.68

n

‐Bu

4

NI‐catalyzed synthesis of quinazolin‐4(3

H

)‐ones from

o

‐amin...

Scheme 4.69

n

‐Bu

4

NI‐catalyzed synthesis of 2,5‐disubstituted 1,3,4‐oxadiazol...

Scheme 4.70

n

‐Bu

4

NI‐catalyzed synthesis of pyrazole skeletons from alkenes a...

Scheme 4.71

n

‐Bu

4

NI‐catalyzed synthesis of Favorskii amides from 1,3‐diaryla...

Scheme 4.72 NH

4

I‐catalyzed synthesis of sulfonamides from sodium sulfonates ...

Scheme 4.73

n

‐Bu

4

NI‐catalyzed synthesis of phosphoryl compounds from alcohol...

Scheme 4.74

n

‐Bu

4

NI‐catalyzed synthesis of carbamoylphosphonates from phosph...

Chapter 5

Scheme 5.1 Syntheses of bromate and iodate compounds through complexation.

Scheme 5.2 Syntheses of iodate compounds through oxidation of iodides.

Scheme 5.3 Cation variation in iodate complexes: (a) Phosphonium salts; (b) ...

Scheme 5.4 Synthesis of bis(amidato)iodate complexes.

Scheme 5.5 Use of iodate complexes in the construction of rotaxanes.

Scheme 5.6 Ligand exchange reactions at iodate complexes.

Scheme 5.7 Synthesis of ω‐iodocarbonyl compounds with Ipy

2

BF

4

.

Scheme 5.8 Radical mechanism involving iodine(I).

Figure 5.1 Conceptual background for iodine(I

−

/I(I)) oxidation catalys...

Figure 5.2 Conceptual background for iodine(I/III) and iodine(III/I) oxidati...

Scheme 5.9 Iodine‐catalyzed Hofmann–Löffler reaction.

Scheme 5.10 Reaction mechanism for the iodine catalytic protocols of Hofmann...

Scheme 5.11 Iodine‐catalyzed β C–H amination.

Scheme 5.12 Iodine‐catalyzed C–N bond formation through radical C–H abstract...

Scheme 5.13 1,3‐Diamines formation through 1,6‐HAT promoted by iodine(I).

Scheme 5.14 Iodine(I/III)‐catalyzed radical intermolecular amination of alip...

Scheme 5.15 Iodine catalyzed intramolecular amination of arenes.

Scheme 5.16 Radical mechanism for the iodine(I)‐promoted C–H amination react...

Scheme 5.17 Iodate‐initiated radical C–H amination reactions.

Scheme 5.18 Radical iodine catalysis for the lactonization of 2‐benzylbenzoi...

Scheme 5.19 Formation of γ‐lactones via cooperative iodine catalysis.

Scheme 5.20 Radical initiation for the iodine‐catalyzed oxygenation of terti...

Scheme 5.21 Nucleophilic fluorination via iodine catalysis.

Scheme 5.22 Synthesis of β‐hydroxy thioethers via alkyliodine(I) catalysis....

Scheme 5.23 Synthesis of diphenylthio enones.

Scheme 5.24 Iodine catalyzed alkene difunctionalization.

Scheme 5.25 Iodate‐initiated radical cyclopropanation reactions.

Scheme 5.26 Synthesis of furans and indolizines via iodine catalysis.

Scheme 5.27 Mechanistic scenario for the synthesis of furans.

Chapter 6

Scheme 6.1 Electrophilic arylation of

N

‐substituted amides.

Scheme 6.2 Oxidative cyclization of acyclic ureas.

Scheme 6.3 Synthesis of carbazoles, carbazolones, and indoloquinolones

via

o...

Scheme 6.4 Iodine(III)‐mediated synthesis of biologically relevant heterocyc...

Scheme 6.5 Synthesis of dihydroquinoxalinones with retention of chirality....

Scheme 6.6 Plausible mechanism for dihydroquinoxalinone synthesis.

Scheme 6.7 C−H amination of biaryl compounds.

Scheme 6.8 Synthesis of chromenone‐indole‐fused heterocycles.

Scheme 6.9 Synthesis of imidazopyrimidines and benzimidazoles fused heterocy...

Scheme 6.10 Effect of substituents on oxidative C–N cyclization.

Scheme 6.11 PIDA‐mediated nucleoside and helicene synthesis.

Scheme 6.12 Biaryl coupling approach for quinolinone derivatives.

Scheme 6.13 Rearrangement reaction of

N‐

phenylbenzamides and proposed ...

Scheme 6.14 Hypervalent iodine‐mediated synthesis of oxindoles and spiroxind...

Scheme 6.15 Synthesis of quinolinone derivatives.

Scheme 6.16 Oxidative synthesis of aporphine scaffold.

Scheme 6.17 Azidoarylation and trifluoromethylation‐arylation of unsaturated...

Scheme 6.18 Synthesis of aza‐heterocycles and acridones.

Scheme 6.19 Homocoupling of alkylarenes, thiophenes, and pyrroles.

Scheme 6.20 Oxidative cross‐coupling reactions mediated by hypervalent iodin...

Scheme 6.21 Oxidative coupling of protected anilines with thiophenes.

Scheme 6.22 C−H arylations mediated by diaryliodonium salts.

Scheme 6.23 C−H amination of arenes mediated by iodine(III) reagents.

Scheme 6.24 C−H amination of heterocycles mediated by iodine(III) reagents....

Scheme 6.25 Direct C−H functionalization at

ortho

‐position of 4‐substituted ...

Scheme 6.26 Direct oxidative C−H functionalization of aniline and thiophene ...

Scheme 6.27 Direct C−H functionalization of nitrogen heterocycles.

Scheme 6.28 Direct C−H functionalization of quinoline

N

‐oxides.

Scheme 6.29 Electrophilic trifluoromethylation of

N

‐heteroarenes.

Scheme 6.30 Photocatalytic C−H trifluoromethylations.

Scheme 6.31 Photocatalytic C−H alkylations and acylations.

Scheme 6.32 Carbazole synthesis

via

oxidative amidation.

Scheme 6.33 Catalytic intramolecular C−H aminations.

Scheme 6.34 Synthesis of phenanthridinones and cinnolines.

Scheme 6.35 Iodine(III) reagent‐catalyzed C−H cycloamination.

Scheme 6.36 Iodine(III)‐catalyzed synthesis of oxoindoles and fused benzimid...

Scheme 6.37 Oxidative intermolecular C−C bond formations.

Scheme 6.38 Oxidative intermolecular C−C/C−N bond formations.

Scheme 6.39 Organocatalytic annulation of benzamides with various alkynes.

Scheme 6.40 I(I/III) catalyzed oxidative intermolecular

para

‐C(sp

2

)−H imidat...

Scheme 6.41 Oxidative formation of C−N and C−O bonds

via

C−H functionalizati...

Chapter 7

Scheme 7.1 General catalytic cycle for aryl iodide‐catalyzed enantioselectiv...

Scheme 7.2 Design concept of chiral iodoarene catalysts.

Figure 7.1 Design principles of

C

1

‐symmetric iodoarene catalysts.

Figure 7.2 Catalyst evolution of chiral iodoarenes divided by the core chira...

Figure 7.3 Solid state structure of a hypervalent iodotetralone

22

.

Scheme 7.3 Schematic representation of the

ortho

‐effect in a comparison of i...

Figure 7.4 Verification of the “

ortho

‐effect” through X‐ray structure analys...

Figure 7.5 DFT‐Optimized structures of chiral oxazoline‐catalysts [13].

Figure 7.6 Catalyst evolution of

C

2

‐symmetric chiral iodoarenes divided by t...

Scheme 7.4 Proposed mechanism (a) and revised transition states with relativ...

Scheme 7.5 Proposed self‐interactions in resorcinol‐based iodine(III) struct...

Figure 7.7 Elucidated structures of resorcinol‐derived chiral iodine(III) sp...

Figure 7.8 Toolbox approach based on 2‐iodoresorcinol with chiral pool‐deriv...

Scheme 7.6 α‐Oxytosylation of propiophenone

14a

.

Scheme 7.7 Performance of iodoarene catalysts in the Kita‐spirolactonization...

Figure 7.9 Examples for different enantioselective transformations with reso...

Chapter 8

Scheme 8.1 1 PIDA‐ and PIFA‐induced dearomatization of phenols in fluoroalco...

Scheme 8.2 Optically active hypervalent iodine(III) compounds reported by pr...

Scheme 8.3 Pelter's attempted asymmetric phenol dearomatization.

Scheme 8.4 Enantioselective dearomative coupling of naphthol 2‐carboxylic ac...

Scheme 8.5 Catalytic utilizations of hypervalent iodine reagents.

Scheme 8.6 Catalytic hypervalent iodine‐induced dearomative spirocyclization...

Scheme 8.7 Asymmetric dearomative coupling employing the catalytic chiral sp...

Scheme 8.8 Enantioselective dearomative

ortho

‐spirocyclization employing the...

Scheme 8.9 Series of atropisomeric chiral binaphthyl iodides.

Scheme 8.10 Structural comparison of

pre‐3a

, 2,2′‐diiodo‐1,1′‐binaphth...

Scheme 8.11 Computational mechanistic study of the asymmetric dearomative sp...

Scheme 8.12 Ishihara

C

2

‐symmetric hypervalent iodine catalyst for the asymme...

Scheme 8.13 Structure of the Ishihara

C

2

‐symmetric chiral hypervalent iodine...

Scheme 8.14 Second‐generation Ishihara catalyst for the asymmetric dearomati...

Scheme 8.15 Asymmetric dearomative

ortho

‐spirocyclization of phenols employi...

Scheme 8.16 Application of

pre‐7b

to the total synthesis of (−)‐maldox...

Scheme 8.17 Asymmetric dearomative

ortho

‐spirocyclic cycloetherification of ...

Scheme 8.18 Asymmetric spiroetherification of

17

employing the modified cata...

Scheme 8.19 Asymmetric spirocyclic amination of the naphtholic sulfonamide a...

Scheme 8.20 Asymmetric spirocyclic arylation of

21

to

22

.

Scheme 8.21 New chiral hypervalent iodine(III) catalysts for the asymmetric ...

Scheme 8.22 Unique nonaromatic chiral diiodides (

M

)–

pre‐28a

–

c

.

Scheme 8.23 New triazole‐based chiral aryl iodides synthesized by Nachtsheim...

Scheme 8.24 Dearomative

para

‐spirocyclization of phenols employing the chira...

Scheme 8.25 Desymmetrization strategy for performing asymmetric dearomative

Scheme 8.26 Birman's chiral isoxazoline catalyst for the asymmetric dearomat...

Scheme 8.27 First catalytic case for the formation of enantioselective

o

‐qui...

Scheme 8.28 Enantioselective formations of

p

‐quinol by Harned and Muñiz.

Scheme 8.29 Indane‐based chiral hypervalent iodine catalyst for the dearomat...

Scheme 8.30 Indane‐based chiral hypervalent iodine catalyst for the dearomat...

Scheme 8.31 Tandem intramolecular

p

‐lactonization and asymmetric dearomative...

Scheme 8.32 General pathways and mechanism of the dearomatization of phenol....

Scheme 8.33 Asymmetric dearomatization of phenol via the associative pathway...

Chapter 9

Figure 9.1 General mechanistic considerations in iodine(III)‐catalyzed alken...

Figure 9.2 Key precedents in enantioselective intermolecular vicinal dioxyge...

Figure 9.3 Catalytic, enantioselective diacetoxylation of unsubstituted styr...

Figure 9.4 Enantioselective catalytic diacetoxylations of styrene derivative...

Figure 9.5 Competing pathways in the enantioselective, catalytic diacetoxyla...

Figure 9.6 Catalytic, enantioselective alkoxylactonization of internal alken...

Figure 9.7 Catalytic, enantioselective hydroxylactonization of alkenyl benzo...

Figure 9.8 Catalytic, enantioselective fluorolactonizations reported by Jaco...

Figure 9.9 Catalytic, enantioselective oxyfluorination reactions. (a) 1,3‐di...

Figure 9.10 (a) Catalytic, enantioselective sulfonyloxylactonization of 4‐pe...

Figure 9.11 (a) Catalytic, racemic cyclization of

N

‐alkenyl benzamides. (b) ...

Figure 9.12 (a) Tandem alkoxylation/oxidative rearrangement of 1,1‐diaryl al...

Figure 9.13 (a) Enantioselective, intramolecular diamination reactions promo...

Figure 9.14 (a) Enantioselective, intermolecular diamination of styrenes pro...

Figure 9.15 (a) Enantioselective fluoroamination promoted by a stoichiometri...

Figure 9.16 (a) Catalytic, enantioselective fluoroamination of cinnamyl tosy...

Figure 9.17 Divergent mechanisms in fluoroaziridine and fluoropyrrolidine pr...

Figure 9.18 Catalytic enantioselective amino‐ and oxyfunctionalization of α‐...

Figure 9.19 (a) Catalytic, vicinal difluorination of terminal alkenes report...

Figure 9.20 (a) Catalytic, diastereoselective difluorination of internal and...

Figure 9.21 Catalytic, enantioselective difluorination of unsubstituted styr...

Figure 9.22 (a) Catalytic, enantioselective difluorination of

N

‐

tert

‐butylci...

Figure 9.23 (a) Catalytic, enantioselective difluorinative rearrangement of ...

Figure 9.24 Catalytic, enantioselective 1,1‐difluorination of α‐bromostyrene...

Figure 9.25 (a) Catalytic, vicinal dichlorination of terminal olefins report...

Figure 9.26 (a) Enantioselective alkoxyarylation of internal alkenes by stoi...

Figure 9.27 Catalytic, enantioselective fluoroarylation reported by Gilmour....

Figure 9.28 (a) Stereospecificity of the fluoroarylation of allyl aryl ether...

Figure 9.29 Catalytic, enantioselective Wagner–Meerwein rearrangements repor...

Figure 9.30 Alternative mechanisms for enantioselective

syn

difunctionalizat...

Figure 9.31 Proposed mechanism of the

anti

‐selective aryl rearrangement reac...

Figure 9.32 (a) Kinetic isotope effect (KIE) experiments used to establish t...

Chapter 10

Scheme 10.1 General catalytic cycle of organoiodine(III) catalysis for oxida...

Scheme 10.2 General catalytic cycle of hypoiodite catalysis for oxidative co...

Scheme 10.3 First example of the organoiodine‐catalyzed α‐C–O coupling of ca...

Scheme 10.4 Chiral organoiodine‐catalyzed enantioselective α‐oxytosylation o...

Scheme 10.5 Mechanistic consideration of the enantioselective α‐oxytosylatio...

Scheme 10.6 Highly enantioselective α‐oxytosylation of enol esters under cat...

Scheme 10.7 Highly enantioselective α‐oxytosylation using NHI

8

as an “omnip...

Scheme 10.8 Enantioselective oxylactonization of ketocarboxylic acid [39, 42...

Scheme 10.9 The first chiral organoiodine(III)‐catalyzed enantioselective α‐...

Scheme 10.10 Enantioselective α‐fluorination of indanone‐derived β‐keto este...

Scheme 10.11 Proposed mechanism of the enantioselective α‐fluorination [46]....

Scheme 10.12 Enantioselective α‐fluorination using planar chiral catalyst

15

Scheme 10.13 Enantioselective oxidative Friedel–Crafts‐type spirocyclization...

Scheme 10.14 Enantioselective cascade oxidative spirocyclization [53].

Scheme 10.15 Oxidative α‐oxyacylation of carbonyls using iodine‐based cataly...

Scheme 10.16 Summarization of the oxidative α‐coupling of carbonyls using in...

Scheme 10.17 Chiral ammonium hypoiodite‐catalyzed oxidative cycloetherificat...

Scheme 10.18 Mechanistic consideration of hypoiodite/H

2

O

2

or ROOH catalysis ...

Scheme 10.19 Enantioselective oxidative α‐azidation of β‐ketoesters [86]....

Scheme 10.20 Synergistic chiral ammonium hypoiodite/imine catalysis for the ...

Chapter 11

Figure 11.1 Classes of iodine(V) compounds for oxidations.

Scheme 11.1 Synthetic approach toward DMP using IBX intermediates.

Scheme 11.2 Synthesis of IBX by Santagostino

et al

.

Figure 11.2 Selected examples of hypervalent iodine(V) compounds derived fro...

Scheme 11.3 Various applications for the IBX/DMP‐mediated oxidation of alcoh...

Scheme 11.4 Representative uses of IBX [71] and DMP [72] in total syntheses....

Scheme 11.5 Selected examples for carbonyl dehydrogenation with IBX.

Scheme 11.6 Selected uses of the IBX‐mediated dehydrogenation in total synth...

Scheme 11.7 Selected oxidative dearomatizations embedded in cascade reaction...

Scheme 11.8 Selected oxidative dearomatizations in natural product syntheses...

Scheme 11.9 IBX‐mediated oxidative aromatizations.

Scheme 11.10 Oxidative dehomologation of various substrates.

Scheme 11.11 Oxidative dehomologation of primary alcohols.

Figure 11.3 A selection of iodylarenes.

Scheme 11.12 Selected synthetic applications of PhIO

2

and its derivatives....

Figure 11.4 Selected examples for immobilized IBX derivatives.

Scheme 11.13 Synthesis of solid‐supported IBX derivatives by

Rademann

and

Gi

...

Figure 11.5 Recyclable hypervalente iodine(V) systems.

Scheme 11.14 Selected examples for the utilization of recyclable iodine(V) c...

Scheme 11.15 Selected examples of catalytic processes with iodine(V) species...

Scheme 11.16 Applications of catalytical systems based on IBS.

Chapter 12

Figure 12.1 Aldehyde‐promoted aerobic oxidation of iodoarenes provides acces...

Figure 12.2 Aldehyde‐promoted aerobic oxidation proceeds by the addition of ...

Figure 12.3 Upon standing for several weeks, an aerated solution of iodobenz...

Figure 12.4 Aerobic synthesis of hypervalent iodine(V) reagents was achieved...

Figure 12.5 Hydrogen peroxide reacts with (ditrifluoroacetoxy)iodobenzene to...

Figure 12.6 The combination of hydrogen peroxide and acetic anhydride genera...

Figure 12.7

In situ

generation of trifluoroperacetic acid from UHP and trifl...

Figure 12.8 H

2

O

2

was combined with concentrated HCl to form hypochlorous aci...

Figure 12.9 Diaryliodonium triflates were synthesized using UHP in a sustain...

Figure 12.10 (a) RuCl

3

‐mediated disproportionation of initially formed hyper...

Figure 12.11 Electrochemical synthesis of 4‐(difluoroiodo)nitrobenzene (

66

) ...

Figure 12.12 Electrochemical synthesis of 4‐(difluoroiodo)toluene (

67

) was c...

Figure 12.13 A fluorinated alcohol solvent such as trifluoroethanol (TFE) is...

Figure 12.14 Electrochemical synthesis of both symmetric and unsymmetric dia...

Figure 12.15 Iodoarene (

76

) with quaternary ammonium moiety obviates the nee...

Figure 12.16 Tetramethylammonium salts of iodophenylsulfonates and iodobenzo...

Figure 12.17 Anodically generated bis(hexafluoroisopropoxy) adduct under flo...

Figure 12.18 Electrochemical oxidation of 2‐iodobenzoic acid (

88

) leads to b...

Figure 12.19 Synthesis of polymer‐supported (diacetoxyiodo)arenes using H

2

O

2

Figure 12.20 Examples of polymer‐supported hypervalent iodine(V) reagents th...

Figure 12.21 Oxone® is used as a terminal oxidant for (a) magnetic nanoparti...

Figure 12.22 Fluorous hypervalent iodine‐mediated oxidation of hydroquinone ...

Figure 12.23 Fluorous hypervalent iodine compounds can be utilized for the o...

Figure 12.24 Aerobically generated hypervalent iodine(III) intermediates are...

Figure 12.25 Utilization of aerobically generated hypervalent iodine(III) re...

Figure 12.26 Synthesis of substituted oxadiazoles was carried out using O

2

a...

Figure 12.27 Spirocyclization of

N

‐oxy‐amides was achieved by photoinduced a...

Figure 12.28 (a) Aerobically generated (2‐

tert‐

butylsulfonyl)iodylbenz...

Figure 12.29

α

‐Functionalization of carbonyl compounds is exemplified b...

Figure 12.30 Enantioselective

α

‐tosyloxylation of ketones was achieved ...

Figure 12.31 (a) Hypervalent iodine‐catalyzed synthesis of lactones was achi...

Figure 12.32 Hypervalent iodine‐catalyzed oxidative C–C coupling with

m

‐CPBA...

Figure 12.33 Asymmetric spirocyclization was achieved using chiral iodoarene...

Figure 12.34 Iodoarene‐catalyzed (a) C(sp

2

)–H and (b) C(sp

3

)–H functionaliza...

Figure 12.35 Hypervalent iodine‐catalyzed C–H amination was achieved using (...

Figure 12.36 (a) Hypervalent iodine‐catalyzed

syn

‐diacetoxylation of alkenes...

Figure 12.37 Asymmetric (a) vicinal difluorination and(b) gem difluorina...

Figure 12.38 Hypervalent iodine‐catalyzed asymmetric diamination of olefins ...

Figure 12.39 Iodomesitylene‐catalyzed oxidative cleavage of C−C unsaturated ...

Figure 12.40 2‐(4‐Iodophenoxy)acetic acid (

185

)‐catalyzed oxidation of pheno...

Figure 12.41 Oxone® is often used as the terminal oxidant for various hyperv...

Figure 12.42 Catalytic oxidation of alcohols in the presence of 2‐iodobenzoi...

Figure 12.43 Iodoarene‐catalyzed (a) oxidation of primary and secondary alco...

Figure 12.44 Catalytic oxidation of phenols by 2‐iodobenzenesulfonic acid de...

Figure 12.45

(

a) Cyclization of

N

‐allyamides in the presence of Selectflour a...

Figure 12.46 Selectflour is used as a terminal oxidant for iodoarene‐catalyz...

Figure 12.47 Bromocyclization of alkenecarboxylic acids to bromolactones was...

Figure 12.48 Hypervalent iodine‐catalyzed substrate functionalizations with ...

Figure 12.49 The first example of hypervalent iodine electrocatalysis was re...

Figure 12.50 Iodoarene and Ru co‐catalyzed C–H hydroxylation of benzamide de...

Figure 12.51 Anodically generated hypervalent iodine intermediates were used...

Chapter 13

Figure 13.1 Applications of iodine.

Figure 13.2 Annual production of acetic acid.

Figure 13.3 The uses of acetic acid.

Figure 13.4 Feedstock choices and process routes for acetic acid [7].

Figure 13.5 BASF acetic acid process.

Figure 13.6 Monsanto acetic acid process.

Figure 13.7 Flow diagram of the Monsanto process.

Figure 13.8 Acetic acid production facility (courtesy of Daicel Co.).

Figure 13.9 Cativa acetic acid process.

Figure 13.10 Composition of a pine tree.

Figure 13.11 Flow diagram of a typical Kraft pulping process.

Figure 13.12 Components in tall oil fraction.

Figure 13.13 Disproportionation of fatty acids in tall oil with iodine catal...

Figure 13.14 Disproportionation of resin acids.

Figure 13.15 Synthesis of photoinitiators.

Figure 13.16 Decomposition of photoinitiator.

Figure 13.17 High‐performance photoresists.

Figure 13.18 Solubility of photoinitiators.

Figure 13.19 Synthesis of (4‐alkoxyphenyl) phenyliodonium salts.

Figure 13.20 Commercially available photoinitiators.

Figure 13.21 Photoinitiators based with a coumarin moiety.

Figure 13.22 Fluorine‐based repellent.

Figure 13.23 Typical production process of fluorinated repellents.

Figure 13.24 Schematic structural morphology of TPEs.

Figure 13.25 Iodine transfer polymerization mechanism.

Figure 13.26 Several examples of items obtained by ITP (courtesy of Daikin)....

Figure 13.27 Organo‐catalyzed controlled polymerization (OCCP).

Figure 13.28 Initiators (up) and organic iodine catalysts (down).

Figure 13.29 An image of dispersions of dispersant with random copolymer [le...

Figure 13.30 Superabsorbent polymer (SAP) (courtesy of Sanyo).

Figure 13.31 Organoiodine chain transfer agents.

Figure 13.32 Network structure of SAP. (a) Conventional FRP, (b) ITP.

Figure 13.33 Retention capacity of the base SAP.

Figure 13.34 Dye for DSSC.

Figure 13.35 Dye‐sensitized solar cells.

Figure 13.36 DSSC (left) and IoT device powered by DSSC (right) (courtesy of...

Figure 13.37 Synthesis of polyamide 66 and polyamide 6.

Figure 13.38 Degradation of polyamide by O

2

and light.

Figure 13.39 Stabilization mechanism of polyamide.

Guide

Cover

Table of Contents

Title Page

Copyright

Preface

Begin Reading

Index

WILEY END USER LICENSE AGREEMENT

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Iodine Catalysis in Organic Synthesis

Edited by Kazuaki Ishihara and Kilian Muñiz

Editors

Prof. Kazuaki IshiharaNagoya UniversityGraduate School of EngineeringB2‐3(611), Furo‐choChikusaNagoya 464‐8603Japan

Prof. Kilian MuñizInst. of Chemical Research of CataloniaAv. Països Catalans 16Tarragona 43007Spain

Cover Design: WileyCover Image: © LuYago/Shutterstock

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Print ISBN: 978‐3‐527‐34829‐9ePDF ISBN: 978‐3‐527‐82955‐2ePub ISBN: 978‐3‐527‐82957‐6oBook ISBN: 978‐3‐527‐82956‐9

Preface

Iodine (symbol I and atomic number 53) is the heaviest of the stable halogens and exists as a lustrous, purplish‐black nonmetallic solid under ambient conditions. It was discovered by the French chemist Bernard Courtois in 1811, and was named two years later by Joseph Louis Gay‐Lussac, after the Greek ἰώδης “violet‐colored.”

The human body needs iodine because iodine plays an essential role in the biosynthesis of thyroid hormones. The iodine needed by the body must come from the diet. Most food contains very little iodine. However, processed food typically contains more iodine due to the addition of iodized salt. Most of the world's iodine is found in the ocean, where it is concentrated by sea life, especially seaweed, and in certain rocks and sediments. The dominant producers of iodine today are Chile and Japan.

Iodine occurs in many oxidation states, including iodide (I−), iodate (IO3−), and various periodate anions. Iodine‐containing compounds are useful as oxidative reagents and catalysts, due to their oxidative ability and ease of attachment to organic compounds. Furthermore, iodine‐containing compounds are useful as Lewis acid catalysts, due to their ability as halogen‐bonding(XB) donors. The XB interactions follow the general trend F < Cl < Br < I, with iodine normally forming the strongest interactions.

Over the past decade, the expansion of hypoiodite(I)‐ and organoiodine(III or V)‐catalyzed oxidative transformations has been unremitting. Iodine‐containing compounds are now some of the most important oxidative catalysts in organic synthesis. Both intramolecular and intermolecular enantioselective oxidative coupling reactions have recently been developed using chiral iodine catalysts. Moreover, iodine‐catalyzed oxidative reactions and Lewis acidic reactions are highly attractive from an environmental point of view. Thus, we decided to publish a new book titled “Iodine Catalysis in Organic Synthesis.”

This book focuses on different areas of iodine chemistry and catalysis, which have been selected because they have developed significantly, and, in some cases, completely, over the past few years. Each author is very knowledgeable in his/her particular field of chemistry and can provide a valuable perspective.

It is our strong hope that this book will be an invaluable guide for synthetic chemists in both academic and industrial laboratories.

Kazuaki IshiharaNagoya

Kilian MuñizTarragona

PS:

We launched this book project in January 2020. Unfortunately, Prof. Muñiz passed away on 16 March 2020. However, we inherited his spirit and were able to keep pushing until the book was complete. I pray for Kilian's soul.

Kazuaki Ishihara

1Historical Introduction

Viktor V. Zhdankin

Department of Chemistry and Biochemistry, University of Minnesota Duluth, Duluth, MN, USA

1.1 Discovery of Iodine and Early Studies

Iodine was originally isolated and recognized as a new element early in the nineteenth century. The French industrial chemist Bernard Courtois had noticed that the addition of concentrated sulfuric acid to seaweed ashes resulted in the emission of a violet vapor that could be condensed to the deep purple solid with the metal‐like appearance of the crystals. These observations were first published in November 1813 in the Annales de Chimie[1]. In this original paper, the name “iode,” derived from the Greek word ἰώδης for violet, was first used for the new substance “due to the beautiful violet color of its vapor.” Soon after, J. L. Gay‐Lussac published his initial results on the chemical properties of iodine demonstrating that this was a novel element capable of forming compounds with other elements [2, 3].

Numerous inorganic compounds of polyvalent iodine in the oxidation states +3, +5, and +7 were prepared early in the nineteenth century. In particular, iodine trichloride was first prepared by J. L. Gay‐Lussac by reacting iodine or iodine monochloride with an excess of chlorine under gentle heating [4]. In the same 1814 paper [4], the preparation of potassium iodate by the action of iodine on hot potash lye was described. The history of the inorganic chemistry of iodine was summarized in numerous common textbooks and reference sources [5–9]. Iodine history, chemistry, and applications were discussed in detail in the review commemorating two centuries of iodine research [10].

The preparation of first polyvalent organoiodine compound, (dichloroiodo)benzene 1 (Figure 1.1) was reported by the German chemist C. Willgerodt in 1886 in the Journal fuer Praktische Chemie[11]. Many other organic iodine(III) and iodine(V) compounds were prepared during the 1890s and at the beginning of the twentieth century. In particular, (diacetoxyiodo)benzene 2, iodosylbenzene 3, and iodylbenzene 4 were reported in 1892 [12]; 2‐iodoxybenzoic acid (IBX, 5) in 1893 [13]; and the first example of diaryliodonium salts 6 were reported by C. Hartmann and V. Meyer in 1894 [14].

Figure 1.1 First examples of polyvalent organoiodine compounds reported in 1886–1894.

The early research on organoiodine chemistry was summarized by C. Willgerodt in 1914 in a comprehensive book Die Organischen Verbindungen mit Mehrwertigen Jod describing nearly 500 polyvalent organoiodine compounds [15].

1.2 Iodine Research in the Twentieth Century

During the period between 1914 and 1970s, research activity in the area of organic chemistry of iodine compounds was relatively low and represented mainly by valuable contributions from the laboratories of I. Masson, R. B. Sandin, F. M. Beringer, K. H. Pausacker, A. N. Nesmeyanov, and O. Neilands. This research, dealing mostly with various iodonium compounds, was summarized in the reviews of R. B. Sandin [16] and D. F. Banks [17] published in 1943 and 1966, respectively. A comprehensive list of known at that time iodine(III) and iodine(V) compounds with their physical properties was published by F. M. Beringer and E. M. Gindler in Iodine Abstracts and Reviews in 1956 [18].

Starting from the 1970s, the interest in the chemistry of iodine compounds had significantly increased. At that time, numerous new classes of polyvalent organoiodine compounds were discovered and many useful synthetic applications of these compounds were developed. The concept of hypervalent molecules was originally proposed by J. I. Musher in 1969 [19], and shortly after, the terminologies “hypervalent iodine,” “hypervalent iodine reagents,” “hypervalent iodine compounds,” and “organohypervalent iodine reagents” were broadly introduced in the works of J. C. Martin, R. M. Moriarty, and several other researchers. During the 1980s, polyvalent iodine compounds have achieved the status of valuable synthetic reagents known under the common name of hypervalent iodine reagents.

The foundation of modern hypervalent iodine chemistry was established in the 1980s in the groundbreaking works of G. F. Koser, J. C. Martin, R. M. Moriarty, P. J. Stang, A. Varvoglis, Y. Kita, M. Ochiai, and N. S. Zefirov. The twentieth‐century iodine research was summarized in two books published by A. Varvoglis in 1992 and 1997: a comprehensive monograph The Organic Chemistry of Polycoordinated Iodine[20] and a book on the applications of hypervalent iodine compounds in organic synthesis [21]. Numerous general reviews [22–27], book chapters [28–33], and specialized reviews on phenyliodine(III) carboxylates [34, 35], [hydroxy(tosyloxy)iodo]benzene [36], the chemistry of alkynyliodonium salts [37], electrophilic perfluoroalkylations [38], application of hypervalent iodine in the carbohydrate chemistry [39], carbon–carbon bond formation via hypervalent iodine [40], hypervalent iodine oxidations [41, 42], hypervalent iodine compounds as free radical precursors [43], synthesis of heterocyclic compounds using organohypervalent iodine reagents [44], and the chemistry of benziodoxoles [45] were also published during the 1980s and 1990s.

1.3 Iodine Research in the Twenty‐first Century

During the first two decades of the twenty‐first century, iodine chemistry has experienced explosive development. Six books [46–51] and hundreds of reviews summarizing various aspects of iodine chemistry and applications have been published between 2001 and 2020. Thousands of research works utilizing iodine reagents in organic and inorganic synthesis are currently published every year. Starting from the beginning of the twenty‐first century, the International Conference on Hypervalent Iodine Chemistry (ICHIC) is regularly convened in different countries, the Society of Iodine Science (SIS) holds annual meetings in Japan, and the American Chemical Society presents the National Award for Creative Research and Applications of Iodine Chemistry biennially. The World Iodine Association (www.worldiodineassociation.com) was officially registered in 2017 as an international nonprofit organization established with the main goal of providing information about the purposes, uses, and applications of iodine and its derivatives.

Current surging interest in iodine chemistry is mainly explained by the very useful oxidizing properties of hypervalent iodine reagents, combined with their benign environmental character and commercial availability. Iodine(III) and iodine(V) derivatives are now routinely used in organic synthesis as reagents for various selective oxidative transformations of complex organic molecules. The discovery and utilization of similarities between the transition metal chemistry and the hypervalent iodine chemistry, and in particular, the development of the highly efficient and enantioselective catalytic systems based on the iodine redox chemistry, has added a new dimension to the field of hypervalent iodine chemistry and initiated a major surge of research activity, which is expected to continue in the future.

1.4 Brief History of Iodine Catalysis

A quick SciFinder search on the concept “iodine catalysts” reveals over 10 000 papers published between 1890 and 2020, including about 300 older papers published during the first half of the twentieth century. The first reliable observations of inorganic and organic reactions catalyzed by iodine date back to the early 1900s. For example, J. Brode [52] and J. H. Walton [53] reported in 1904 the catalytic decomposition of hydrogen peroxide in the presence of iodine involving hypoiodite as a key intermediate. L. Bruner in 1902 published a mechanistic study of the catalytic action of iodine on the bromination of benzene, in which the catalytic effect of iodine is explained by the formation of iodine bromide, IBr, as active species [54].

The vast majority of papers on iodine catalysis published between 1900 and 2005 did not involve the oxidation of iodine to the hypoiodite or hypervalent iodine‐active species. These papers almost exclusively deal with the catalytic application of iodine as a Lewis acid or as a radical initiator. In some catalytic reactions, iodide anion is utilized as a strong nucleophile, generating organic iodides RI as intermediate species incorporating the excellent iodide‐leaving group. Such catalysis involving the generation of organic iodides has been employed in the important Monsanto–Cativa industrial process for the production of acetic acid. In this process, the catalytic hydroiodic acid converts the methanol feedstock into methyl iodide, which undergoes Rh‐ or Ir‐catalyzed carbonylation. Hydrolysis of the resulting acetyl iodide regenerates hydroiodic acid and gives acetic acid [55]. The carbonylation of methanol, catalyzed by rhodium in the presence of hydroiodic acid, was originally invented by Monsanto company in the 1960s. In the 1990s, Eastman Chemical Company developed a modification of this industrial process based on the use of lithium iodide as the cocatalyst [56].

A new era in iodine catalysis was opened in 2005 by the discovery of reactions catalyzed by hypervalent iodine species. The similarities between hypervalent iodine species and transition metal‐organic complexes had been widely recognized in the works of many researchers since the end of the twentieth century. At that time, the terminologies “oxidative addition,” “reductive elimination,” “ligand exchange,” and “ligand coupling” became common in mechanistic discussions of the reactions of hypervalent molecules [57]. However, catalytic reactions, typical of transition metals, remained unknown for hypervalent iodine compounds until the beginning of the twenty‐first century.

In 2005, Kita and Ochiai independently reported the catalytic use of aryl iodides, in the presence of stoichiometric m‐chloroperoxybenzoic acid, to perform oxidative dearomatization of phenolic substrates 7 (Scheme 1.1) [58], or α‐acetoxylation of carbonyl compounds 8 (Scheme 1.2) [59], respectively. These reactions involved selective generation of the highly reactive hypervalent iodine(III) species (e.g. 9 in Scheme 1.2) in situ from aryl iodide and terminal oxidant.

Scheme 1.1 Catalytic oxidative spirocyclization reaction of a phenolic substrate in the presence of 4‐iodotoluene.

Scheme 1.2 Catalytic α‐acetoxylation of carbonyl compounds in the presence of iodobenzene.

First examples of the catalytic application of the iodine(V) species in the oxidation of alcohols using Oxone® (2KHSO5•KHSO4•K2SO4) as a stoichiometric oxidant at 70 °C were independently reported by the groups of Vinod [60] in 2005 and Giannis [61] in 2006. A few years later, Ishihara and coworkers discovered that 2‐iodoxybenzenesulfonic acid (IBS) can act as an extremely active catalyst for the selective oxidation of alcohols to aldehydes, ketones, carboxylic acids, and enones with Oxone [62]. While chemical reactions catalyzed by hypervalent iodine species were discovered only in 2005, the electrochemical generation of iodine(III) species in situ from catalytic amounts of iodoarenes (0.05–0.2 equiv), and the use of these species as the in‐cell mediators in electrochemical fluorination reactions, had been known since 1994 [63].

First examples of enantioselective reactions catalyzed by chiral aryl iodides [64–69] or chiral ammonium iodides [70] were reported by several research groups in 2007–2010. These groundbreaking initial reports were followed by a huge wave of publications describing various enantioselective oxidative transformations catalyzed by hypervalent iodine species. A brief historical overview of enantioselective iodine catalysis can be found in the 2019 review of Muñiz and coauthors [71].

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2Concepts in Iodine Catalysis

Kazuaki Ishihara

Graduate School of Engineering, Nagoya University, Nagoya, Japan

2.1 Introduction

Iodine can form inorganic and organic derivatives in various oxidation states (–1, 0, +1, +3, +5, +7), and the structural features and reactivity patterns of these iodine compounds are, in many respects, similar to those of the derivatives of heavy transition metals. However, in contrast to heavy metals, iodine is both environmentally friendly and relatively inexpensive. About 30 000 tons of iodine are produced annually, and the world's total reserves are estimated to be 15 million metric tons, located mainly in Chile and Japan [1].

Iodine readily disproportionates into iodide and hypoiodites as well as other iodine–oxygen species in basic aqueous solutions according to the Latimer diagrams in Scheme 2.1 [2, 3]. In contrast, iodine is stable against disproportionation in acidic solutions, near pH 0. For neutral solutions around pH 7, which are probably closest to most experimental conditions, a very unfavorable equilibrium constant of 2.0 × 10−13 has been determined for the reaction between water and iodine [3]. Therefore, water and alcohols can react with molecular iodine to give hydroiodic acid (HI).

Scheme 2.1