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Synlett 2009(17): 2715-2739  
DOI: 10.1055/s-0029-1217979
ACCOUNT
© Georg Thieme Verlag Stuttgart ˙ New York

Catalytic Asymmetric Aziridination with Catalysts Derived from VAPOL and VANOL

Yu Zhang, Zhenjie Lu, William D. Wulff*
Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
Fax: +1(517)3531793; e-Mail: wulff@chemistry.msu.edu;
Further Information

Publication History

Received 12 February 2009
Publication Date:
16 September 2009 (online)

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Abstract

This Account describes the discovery and development of the catalytic asymmetric aziridination reaction (AZ reaction) that has been the subject of efforts in our laboratory over the last 12 years. The optimized catalyst system involves catalysts generated from either the VAPOL or VANOL ligand and triphenyl borate. These catalysts are effective for formation of aziridines from the reac­tion of imines that bear a N-benzhydryl substituent with stabilized diazo compounds including the commercially available ethyl diazoacetate (EDA). The reaction is general for N-benzhydryl im­ines prepared from electron-rich and electron-poor aromatic aldehydes, as well as from primary, secondary and tertiary aliphatic aldehydes. This reaction is highly enantioselective and diastereo­selective giving cis-3-substituted aziridine-2-carboxylates in excellent yields. This Account presents the scope of the AZ reaction as defined by the work that has been done in our laboratory up to the present time, as well as applications of the resulting aziridines that have been demonstrated to date.

1 Introduction

2 Asymmetric Aziridination of Ethyl Diazoacetate with ­Imines

2.1 Discovery of the Original Catalytic System

2.2 Optimized Catalytic Asymmetric Aziridination System

2.3 Deprotection and Activation of Aziridine-2-carboxylates

3 Applications of Catalytic Asymmetric Aziridination

3.1 Ring Expansion of Aziridines to Oxazolidinones

3.2 Asymmetric Aziridination with Diazomethyl Vinyl ­Ketones

3.3 Diastereoselective Alkylation of cis-Aziridine-2-carboxylates

3.4 Synthetic Applications of the Catalytic Asymmetric Aziri­dination Reaction

4 Conclusion and Outlook

Key words

aziridination - Lewis acids - chiral ligands - asymmetric catalysis