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Synlett 2002(3): 0381-0393
DOI: 10.1055/s-2002-20448
ACCOUNT
© Georg Thieme Verlag Stuttgart · New York

Selective Bond Cleavage of the β-Lactam Nucleus: Application in Stereocontrolled Synthesis

Benito Alcaide*, Pedro Almendros
Departamento de Química Orgánica I, Facultad de Química, Universidad Complutense, 28040-Madrid, Spain
Fax: +34(91)3944103; e-Mail: alcaideb@quim.ucm.es;
Further Information

Publication History

Received 26 July 2001
Publication Date:
05 February 2007 (online)

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Abstract

Besides their biological activity, the importance of β-lactams as synthetic intermediates has been widely recognized in organic synthesis because ring cleavage of any of the four single bonds of the β-lactam system is enhanced by ring strain. Selective bond cleavage of the 2-azetidinone ring coupled with further interesting synthetic transformations renders these fascinating molecules powerful synthetic building blocks. Opening of the β-lactam ring can occur through cleavage of any of the single bonds of the four-membered ring. However, the sequential or simultaneous fragmentation of two bonds of the 2-azetidinone ring has been seldom reported. The present account is a survey of the recent salient synthetic achievements exploiting selective bond cleavage of the β-lactam nucleus, with particular emphasis to diastereoselective processes. The usefulness of these substrates for the preparation of substances of biological interest, including α-amino acids, β-amino acids, indolizidines, pyrrolizidines, eight-membered lactams, and complex natural products is presented. The majority of the reviewed work will be centered in significant results from our research group. However, interesting results from others workers will be included.

1 Introduction

2 Selective Bond Cleavage of the 2-Azetidinone Nucleus

2.1 N1-C2 Bond Breakage

2.2 C2-C3 Bond Breakage

2.3 C3-C4 Bond Breakage

2.4 C4-N1 Bond Breakage

3 Cleavage of Two Bonds of the 2-Azetidinone Ring

4 Summary

Key words

β-lactams - strain energy - selective bond cleavage - rearrangement reactions - stereocontrolled synthesis