Regioselective tandem sulfonylation/cyclization of unsaturated N-substituted enamides with sulfonyl chlorides by copper catalysis

Abstract

The radical cascade cyclization of vinyl-tethered alkenes has become a promising tool for rapidly assembling nonbenzene-fused cyclic skeletons via the cracking of alkenyl C–H bonds, but this approach has been limited to 3-aza-1,5-dienes and five-membered rings have been generated. Here, we developed a radical sulfonylation/cyclization process for unsaturated N-substituted enamides with sulfonyl chlorides to form sulfonylated nonbenzene-fused six/seven-membered rings, which involved regioselective sulfonyl radical addition to the alkene and 6/7-endo cyclization.