Organoselenium Chemistry E-Book

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

Seitenzahl: 496

Veröffentlichungsjahr: 2011

Beschreibung

Selenium-based methods in synthetic chemistry have developed rapidly over the past years and are now offering highly useful tools for organic synthesis. Filling the gap for a comprehensive handbook and ready reference, this book covers all modern developments within the field, including biochemical aspects. The chemistry chapters are organized according to the different reactivities of various selenium compounds and reagents, with each chapter dealing with a special reaction type. Also includes a table with 77Se NMR shifts to aid in practical problems. From the Contents: * Electrophilic and Nucleophilic Selenium * Selenium Compounds in Radical Reactions * Selenium-Stabilized Carbanions * Selenium Compounds with Valency Higher than Two * Selenocarbonyls * Selenoxide Elimination and [2,3]-Sigmatropic Rearrangement * Selenium Compounds as Ligands and Catalysts * Biological and Biochemical Aspects of Selenium Compounds

Leseprobe

Table of Contents

Cover

Related Titles

Title page

Copyright page

Preface

List of Contributors

1 Electrophilic Selenium

1.1 General Introduction

1.2 Addition Reactions to Double Bonds

1.3 Selenocyclizations

2 Nucleophilic Selenium

2.1 Introduction

2.2 Properties of Selenols and Selenolates

2.3 Inorganic Nucleophilic Selenium Reagents

2.4 Organic Nucleophilic Selenium Reagents

3 Selenium Compounds in Radical Reactions

3.1 Homolytic Substitution at Selenium to Generate Radical Precursors

3.2 Selenide Building Blocks

3.3 Solid-Phase Synthesis

3.4 Selenide Precursors in Radical Domino Reactions

3.5 Homolytic Substitution at Selenium for the Synthesis of Se-Containing Products

3.6 Seleno Group Transfer onto Alkenes and Alkynes

3.7 PhSeH in Radical Reactions

3.8 Selenium Radical Anions, SRN1 Substitutions

4 Selenium-Stabilized Carbanions

4.1 Introduction

4.2 Preparation of Selenium-Stabilized Carbanions

4.3 Reactivity of the Selenium-Stabilized Carbanions with Electrophiles and Synthetic Transformations of the Products

4.4 Stereochemical Aspects

4.5 Application of Selenium-Stabilized Carbanions in Total Synthesis

4.6 Conclusion

5 Selenium Compounds with Valency Higher than Two

5.1 Introduction

5.2 Trivalent, Dicoordinated Selenonium Salts

5.3 Trivalent, Tricoordinated Derivatives

5.4 Tetravalent, Dicoordinated Derivatives

5.5 Tetravalent, Tricoordinated Derivatives

5.6 Pentavalent Derivatives

5.7 Hexavalent, Tetracoordinated Derivatives

5.8 Hypervalent Derivatives

6 Selenocarbonyls

6.1 Overview

6.2 Theoretical Aspects of Selenocarbonyls

6.3 Molecular Structure of Selenocarbonyls

6.4 Synthetic Procedures of Selenocarbonyls

6.5 Manipulation of Selenocarbonyls

6.6 Metal Complexes of Selenocarbonyls

6.7 Future Aspects

7 Selenoxide Elimination and [2,3]-Sigmatropic Rearrangement

7.1 Introduction

7.2 Preparation and Properties of Chiral Selenoxides

7.3 Selenoxide Elimination

7.4 [2,3]-Sigmatropic Rearrangement via Allylic Selenoxides

7.5 [2,3]-Sigmatropic Rearrangement via Allylic Selenimides

7.6 [2,3]-Sigmatropic Rearrangement via Allylic Selenium Ylides

7.7 Summary

8 Selenium Compounds as Ligands and Catalysts

8.1 Introduction

8.2 Selenium-Catalyzed Reactions

9 Biological and Biochemical Aspects of Selenium Compounds

9.1 Introduction

9.2 Biological Importance of Selenium

9.3 Selenocysteine: The 21st Amino Acid

9.4 Biosynthesis of Selenocysteine

9.5 Chemical Synthesis of Selenocysteine

9.6 Chemical Synthesis of Sec-Containing Proteins and Peptides

9.7 Selenoenzymes

9.8 Summary

77Se NMR Values

Index

Related Titles

Toru, T., Bolm, C. (eds.)

Organosulfur Chemistry in Asymmetric Synthesis

2008

Hardcover

ISBN: 978-3-527-31854-4

Steinborn, D.

Fundamentals of Organometallic Catalysis

2011

Hardcover: ISBN: 978-3-527-32716-4

Softcover: ISBN: 978-3-527-32717-1

Song, C. E. (ed.)

Cinchona Alkaloids in Synthesis and Catalysis

Ligands, Immobilization and Organocatalysis

2009

Hardcover

ISBN: 978-3-527-32416-3

Zecchina, A., Bordiga, S., Groppo, E. (eds.)

Selective Nanocatalysts and Nanoscience

Concepts for Heterogeneous and Homogeneous Catalysis

2011

Hardcover

ISBN: 978-3-527-32271-8

Cordova, A. (ed.)

Catalytic Asymmetric Conjugate Reactions

2010

Hardcover

ISBN: 978-3-527-32411-8

Bandini, M., Umani-Ronchi, A. (eds.)

Catalytic Asymmetric Friedel-Crafts Alkylations

2009

Hardcover

ISBN: 978-3-527-32380-7

Ackermann, L. (ed.)

Modern Arylation Methods

2009

Hardcover

ISBN: 978-3-527-31937-4

Carreira, E. M., Kvaerno, L.

Classics in Stereoselective Synthesis

2009

Hardcover: ISBN: 978-3-527-32452-1

Softcover: ISBN: 978-3-527-29966-9

Ding, K., Dai, L.-X. (eds.)

Organic Chemistry – Breakthroughs and Perspectives

2012

Softcover

ISBN: 978-3-527-32963-2

The Editor

Prof. Dr. Thomas Wirth

Cardiff University

School of Chemistry

Park Place Main Building

Cardiff CF10 3AT

United Kingdom

All books published by Wiley-VCH are carefully produced. Nevertheless, authors, editors, and publisher do not warrant the information contained in these books, including this book, to be free of errors. Readers are advised to keep in mind that statements, data, illustrations, procedural details or other items may inadvertently be inaccurate.

Library of Congress Card No.: applied for

British Library Cataloguing-in-Publication Data

A catalogue record for this book is available from the British Library.

Bibliographic information published by the Deutsche Nationalbibliothek

The Deutsche Nationalbibliothek lists this publication in the Deutsche Nationalbibliografie; detailed bibliographic data are available on the Internet at <http://dnb.d-nb.de>.

© 2012 Wiley-VCH Verlag & Co. KGaA, Boschstr. 12, 69469 Weinheim, Germany

All rights reserved (including those of translation into other languages). No part of this book may be reproduced in any form – by photoprinting, microfilm, or any other means – nor transmitted or translated into a machine language without written permission from the publishers. Registered names, trademarks, etc. used in this book, even when not specifically marked as such, are not to be considered unprotected by law.

Print ISBN: 978-3-527-32944-1

ePDF ISBN: 978-3-527-64196-3

oBook ISBN: 978-3-527-64194-9

ePub ISBN: 978-3-527-64195-6

mobi ISBN: 978-3-527-64197-0

Preface

Selenium was discovered in 1818 – almost 200 years ago – by the Swedish chemist Jöns Jacob Berzelius. Selenium is a common companion of sulfur, but was named after the goddess of the moon Selene. This indicates the chemical relation to tellurium, named after the Greek word for earth, tellus. Berzelius studied the element selenium and its inorganic compounds in detail. Nowadays, selenium is obtained in the electrolytic refining of copper and its production reaches several thousand tons per year. The first organoselenium derivative (ethyl selenol) was published in 1847 by Wöhler and Siemens. The use of selenium dioxide as an oxidant was described in a patent in 1929. Since that time, selenium and its derivatives have appeared as reagents in organic synthesis. Organoselenium chemistry started blossoming in the early seventies with the discovery of the selenoxide elimination for the introduction of double bonds under mild reaction conditions. Since 1971, the chemistry of selenium and tellurium is also regularly promoted in a conference series (ICCST, International Conference on the Chemistry of Selenium and Tellurium). Several monographs and many review articles have appeared during the last decades. This book summarizes the latest developments with a strong emphasis on the last decade providing an updated picture of the many facets of organoselenium chemistry.

I am very grateful to all the distinguished scientists who have contributed to this book with their time, knowledge, and expertise. I hope that all chapters will not only be a rich source of information, but also a source of inspiration to students and colleagues.

Thomas Wirth

Cardiff, July 2011

List of Contributors

Bhaskar J. Bhuyan

Indian Institute of Science

Department of Inorganic and Physical Chemistry

Bangalore 560 012

India

W. Russell Bowman

Loughborough University

Department of Chemistry

Loughborough, Leics LE11 3TU

UK

João V. Comasseto

Universidade de São Paulo

Instituto de Química

Av. Prof. Lineu Prestes, 748

05508-000 São Paulo-SP

Brazil

Alcindo A. Dos Santos

Universidade de São Paulo

Instituto de Química

Av. Prof. Lineu Prestes, 748

05508-000 São Paulo-SP

Brazil

Józef Drabowicz

Polish Academy of Sciences

Department of Heteroorganic Chemistry

Center of Molecular and Macromolecular Studies

Sienkiewicza 112

Łód 90–363

Poland

and

Jan Długosz University

Institute of Chemistry and Environmental Protection

Armii Krajowej 13/15

Czstochowa 42–200

Poland

Michio Iwaoka

Tokai University

School of Science

Department of Chemistry

Kanagawa 259-1292

Japan

Jarosław Lewkowski

University of Łód

Faculty of Chemistry

Department of Organic Chemistry

Tamka 12; 91-403 Łód

Poland

Toshiaki Murai

Gifu University

Faculty of Engineering

Department of Chemistry

Yanagido, Gifu 501-1193

Japan

Govindasamy Mugesh

Indian Institute of Science

Department of Inorganic and Physical Chemistry

Bangalore 560 012

India

Yoshiaki Nishibayashi

The University of Tokyo

School of Engineering

Bunkyo-ku

Tokyo 113-8656

Japan

Claudio Santi

University of Perugia

Dipartimento di Chimica e Tecnologia del Farmaco

Perugia 06123

Italy

Stefano Santoro

University of Perugia

Dipartimento di Chimica e Tecnologia del Farmaco

Perugia 06123

Italy

Jacek cianowski

Nicolaus Copernicus University

Faculty of Chemistry

Department of Organic Chemistry

Gagarina 7

Toru 87–100

Poland

Fateh V. Singh

Cardiff University

School of Chemistry

Park Place

Cardiff CF10 3AT

UK

Sakae Uemura

Okayama University of Science

Faculty of Engineering

Okayama 700-0803

Japan

Edison P. Wendler

Universidade de São Paulo

Instituto de Química

Av. Prof. Lineu Prestes, 748

05508-000 São Paulo-SP

Brazil

Thomas Wirth

Cardiff University

School of Chemistry

Park Place

Cardiff CF10 3AT

UK

1

Electrophilic Selenium

Claudio Santi and Stefano Santoro

1.1 General Introduction

During the last few decades, organoselenium compounds have emerged as important reagents and intermediates in organic synthesis.

Selenium can be introduced as an electrophile, as a nucleophile, or as a radical and generally it combines chemo-, regio-, and stereoselectivity with mild experimental conditions. Once incorporated, it can be directly converted into different functional groups or it can be employed for further manipulation of the molecule.

Since the discovery in the late 1950s that species of type RSeX add stereospecifically to simple alkenes [1], electrophilic organoselenium compounds provided the synthetic chemist with useful and powerful reagents and the selenofunctionalization of olefins represents an important method for the rapid introduction of vicinal functional groups, often with concomitant formation of rings and stereocenters (Scheme 1.1a and b).

Scheme 1.1 The reactivity of electrophilic selenium reagents.

In addition, electrophilic selenium reagents can be also used for the α-selenenylation of carbonyl compounds (Scheme 1.1c) affording useful intermediates for the synthesis of α,β-unsaturated [2] derivatives or 1,2-diketones through a seleno-Pummerer reaction [3].

Oxidation of selenides to the corresponding selenoxide for the synthesis of α,β-unsaturated compounds represents a current topic in organic chemistry and has been used successfully also in structurally complex product synthesis. An example has been very recently reported in which the electrophilic selenenylation followed by an oxidative elimination represent a crucial step in the total synthesis of heptemerone G, a diterpenoid fungi-derived with interesting antibacterial activity (Scheme 1.2) [4].

Scheme 1.2 Electrophilic selenium reagent in the total synthesis of heptemerone G.

The kinetic lithium enolate 1, trapped as trimethysilyl derivatives, reacts with PhSeCl affording the selenide 2 that, after oxidation with metachloroperbenzoic acid, is converted into the enone 3 from which the heptemerone G can be prepared in some additional steps.

The treatment of selenides with tin hydrides, in the presence of AIBN, produces the homolytic cleavage of the carbon–selenium bond generating a carbon radical and opening the way for interesting radical reactions.

An elegant application was reported for the total synthesis of (+)-Samin (Scheme 1.3). The selenide 4 was subjected to radical deselenenylation conditions affording the tetrahydrofurane derivative 5 following a 5-exo-trig radical cyclization mechanism. From 5, (+)-Samin was obtained through a few classical steps [5].

Scheme 1.3 Electrophilic selenium reagent in the total synthesis of (+)-Samin.

The main aspects of organoselenium chemistry have been described in a series of books [6] and review articles and, in recent times, the synthesis of chiral selenium electrophiles as well as their applications in asymmetric synthesis represents a very interesting field of interests for many research groups [7].

In this chapter, we take in consideration some general aspects of the chemistry promoted by electrophilic selenium reagents by reporting selected examples and some more recent and innovative applications.

1.1.1 Synthesis of Electrophilic Selenium Reagents

Some phenylselenenyl derivatives such as chloride, bromide, and N-phenylselenophthalimide [8] are nowadays commercially available and represent the most common electrophilic reagents used to introduce selenium into organic molecules. Otherwise, in a more general procedure, very versatile precursors for the preparation of various electrophilic selenium species are the corresponding diselenides 6. They can be easily converted into selenenyl halides 7, 8 by treatment with sulfuryl chloride or chlorine in hexane and bromine in tetrahydrofuran, respectively (Scheme 1.4).

Scheme 1.4 Electrophilic selenium reagents.

The use of halides in synthesis often gives rise to side processes due to the nucleophilicity of the halide anions. For this reason, a series of new selenenylating agents with nonhalide counterions have been reported.

Some of them were directly prepared starting from the appropriate selenenyl halide with silver salts such as hexafluorophosphate 9 [9], hexafluoroantimoniate 10 [10], tolylsulfonate 11 [11], and triflate 12 [12].

This latter is probably the most commonly used electrophilic selenium reagent even if, in many cases, the stoichiometric amount of trifluoromethanesulfonic acid formed is not compatible with the stability of the substrates and/or of the products. More recently, Tingoli reported a similar procedure to prepare the N-saccharin derivatives 13 containing a sulfonamide anion that is scarcely nucleophilic and generating saccharin that is a very weak acidic species [13].

In other cases, the electrophilic reagent can be more conveniently produced by the in situ oxidation of 6 with several inorganic reagents: KNO3 [14], CuSO4 [15], Ce(NH4)2(NO2)6 [16], Mn(OAc) [17], or nitrogen dioxide [18]. Among these, starting from diphenyl diselenide, (NH4)2S2O8 [19] produces the strongly electrophilic phenylselenenyl sulfate (PSS) through a mechanism that reasonably involves an electron transfer or an S2 reaction. A product derived from a single electron transfer has been proposed also as an intermediate in the reaction of diphenyl diselenide with 1,2-dicyanonaphthalene [20] that leads to the formation of the phenylselenenyl cation as depicted in Scheme .