Cu-Catalyzed Conversion of Propargyl Acetates to E-α,β-Unsaturated Amides via Ketenimine Formation with Sulfonyl Azides

Abstract

The reaction between readily accessible propargyl acetates and sulfonyl azides in presence of CuI catalyst yielded trans α, β-unsaturated N-tosylamides via N-sulfonyl ketimine formation followed by a probable 1,3-OAc migration ([3,3]-sigmatropic rearrangement). The reaction was very general allowing all kinds of substitution, i.e. alkyl, aryl (electron donating, withdrawing and neutral), heteroaryl and vinyl groups, on the C-terminal of acrylamide. Also, the method afforded the products at ambient temperature with excellent diastereoselectivity and in moderate to good yields.