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Synthesis 2002(12): 1625-1642
DOI: 10.1055/s-2002-33635
REVIEW
© Georg Thieme Verlag Stuttgart · New York

Recent Developments in the Chemistry of Lithiated Epoxides

David M. Hodgson*, Emmanuel Gras
Dyson Perrins Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QY, UK
Fax: +44(1865)275674; e-Mail: david.hodgson@chem.ox.ac.uk;
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Publication History

Received 17 June 2002
Publication Date:
05 September 2002 (online)

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Abstract

Although the lithium base-induced β-elimination of epoxides to allylic alcohols is a well-known reaction, α-lithiation has also been described many times. The resulting lithiated epoxides, first postulated as intermediates by Cope in 1951, have been invoked in a wide range of reactions, with their carbenoid properties allowing for very different reactivities. This review covers the recent advances (˜1996 - mid 2002) in the rich chemistry of these main-group metal carbenoids, especially their generation by enan­tioselective α-deprotonation.

  • 1 Introduction

  • 2 Carbenoid Chemistry of Lithiated Epoxides: C-H Insertion and 1,2-Shifts

  • 2.1 Transannular C-H Insertion

  • 2.2 Transannular Rearrangement versus 1,2-Shift of Hydrogen

  • 2.3 1,2-Shifts

  • 2.4 Cyclopropanations

  • 3 Carbenoid Chemitry of Lithiated Epoxides: Reductive Alkylation

  • 3.1 Olefin Formation: Allylic Alcohols via Reductive Alkylation

  • 3.2 Olefin Formation versus C-H Insertion

  • 3.3 Olefin Formation versus Electrophile Trapping

  • 4 Electrophile Trapping of Lithiated Epoxides

  • 4.1 Lithiated Epoxides Bearing Anion Stabilising Groups

  • 4.1.1 Transmetallation of Stabilised Lithiated Epoxides

  • 4.1.2 Sulfonyl-stabilised Lithiated Epoxides

  • 4.1.3 Carbonyl-stabilised Lithiated Epoxides

  • 4.1.4 Oxazolinyl-stabilised Lithiated Epoxides

  • 4.1.5 Imine-substituted Lithiated Epoxides

  • 4.1.6 Trifluoromethyl-substituted Lithiated Epoxides

  • 4.1.7 Silyl-stabilised Lithiated Epoxides in Synthesis

  • 4.1.8 Phenyl-stabilised Lithiated Epoxide

  • 4.2 ‘Remote’ Stabilisation of a Lithiated Epoxide

  • 4.3 Generation of Non-stabilised and Destabilised Lithiated Epoxides

  • 4.3.1 Desulfinylation of Sulfinyloxiranes

  • 4.3.2 Deprotonation of ‘Simple’ Epoxides

  • 5 Concluding Remarks

Key words

asymmetric synthesis - carbanions - carbenoids - epoxides - rearrangements