Alkyne Carbonylation by Radicals: Tin-Radical-Catalyzed Synthesis of α-Methylene Amides from 1-Alkynes, Carbon Monoxide, and Amines

A convergent synthesis of α‐methylene amides exploits a hybrid radical/ionic concept in which radical carbonylation of alkynes is followed by ionic trapping of the resulting carbonyl‐containing radical species with amines (see scheme). The reaction of substituted terminal alkynes with pressurized CO, Bu3SnH, and 2,2′‐azobisisobutyronitrile in the presence of a large excess of amines gave good yields of the corresponding α‐methylene amides.