Catalytic CN Bond Alkynylation of <i>N</i>‐Benzylic Sulfonamides with Terminal Alkynes

Abstract

Abstract A new cross‐coupling reaction of N ‐benzylic sulfonamides with terminal alkynes for the synthesis of internal alkynes is reported. In the presence of 5 mol% of (Tf) 2 NH/Bi(OTf) 3 (1:1), a broad range of N ‐benzylic sulfonamides react smoothly with arylacetylenes to afford structurally diverse internal alkynes in moderate to excellent yields. We reasoned that vinyl cations could be formed by the regioselective attack of terminal alkynes with benzyl cations generated in situ from N ‐benzylic sulfonamides under acidic conditions, which then eliminated to form a carbon‐carbon triple bond.