Aza-Darzens Asymmetric Synthesis of N-(p-Toluenesulfinyl)aziridine 2-Carboxylate Esters from Sulfinimines (N-Sulfinyl Imines)

Franklin A. Davis,* Hu Liu, Ping Zhou,† Tianan Fang, G. Venkat Reddy, and Yulian Zhang
Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, and Department of Chemistry, Drexel University, Philadelphia, Pennsylvania 19104
J. Org. Chem., 1999, 64 (20), pp 7559–7567
DOI: 10.1021/jo990907j
Publication Date (Web): September 16, 1999
Copyright © 1999 American Chemical Society
*

 E-mail:  fdavis@astro.ocis.temple.edu.

,
†

 Drexel University.

Abstract

Abstract Image

The one-step aza-Darzens reaction of sulfinimines 2 with lithium α-bromoenolates readily affords diversely substituted cis and trans N-sulfinylaziridine 2-carboxylate esters 3 and 7 in good yield and excellent diastereoselectivity. Higher yields, but lower de's, result when a mixture of the α-bromo ester and 2 are treated with base. The N-sulfinyl group is transformed, nearly quantitatively, without ring opening, into the N-tosyl activating group by oxidation with m-CPBA. Selective removal of the N-sulfinyl group in aziridines 3a and 3h with TFA/H2O affords 1H-aziridines 21 which are difficult to prepared by other means. However, C(3) activated azirines such as 3b undergo ring-opening under these conditions. Alternatively, the N-sulfinyl group, even in C(3)-activated aziridines, was selectively and efficiently removed by treatment of the aziridine with 2 equiv of MeMgBr.

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History

  • Published In Issue October 01, 1999
  • Received June 3, 1999

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