Cu-Catalyzed Conversion of Propargyl Acetates to E-α,β-Unsaturated Amides via Ketenimine Formation with Sulfonyl Azides
Yalla Kiran Kumar, Gadi Ranjith Kumar and Maddi Sridhar Reddy*
*Medicinal & Process Chemistry Division, CSIR-Central Drug Research Institute, BS-10/1, Sector 10, Jankipuram Extension, Sitapur Road, P.O. Box 173, Lucknow 226031, India, Email: msreddycdri.res.in
Y. K. Kumar, G. R. Kumar, M. S. Reddy, J. Org. Chem., 2014, 79, 823-828.
N-Sulfonyl ketenimine formation followed by a probable 1,3-OAc migration ([3,3]-sigmatropic rearrangement) enables a synthesis of trans-α,β-unsaturated N-tosylamides from readily accessible propargyl acetates and sulfonyl azides in the presence of CuI as catalyst. The reaction is very general and affords products at ambient temperature with excellent diastereoselectivity in good yields.
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