Highly Diastereoselective [3 2] Cycloadditions between Nonracemic p-Tolylsulfinimines and Iminoesters:An Efficient Entry to Enantiopure Imidazolidines and Vicinal Diaminoalcohols

Abstract

A new procedure for the asymmetric synthesis of imidazolidines and vicinal diamines is reported. The 1,3-dipolar cycloaddition between non racemic p-tolylsulfinimines and azome thine ylides generated in situ from - iminoesters and LDA produces N-sulfi nylimidazolidines with a high degree of stereocontrol. In contrast, the presence of Lewis acids promotes formation of the cycloadducts through a highly dia stereoselective process with opposite stereochemistry. Subsequent transfor mations of the imidazolidines including oxidative, reductive, and hydrolytic processes that provide easy access to vicinal diaminoalcohols have been ex plored. Among these, reductive cleav age of the aminal with LiAlH4 is an extremely efficient and general reaction for the synthesis of enantiopure N sulfinyl-N -benzyldiaminoalcohols