Alkyne carbonylation by radicals: Tin-radical-catalyzed synthesis of α-methylene amides from 1-alkynes, carbon monoxide, and amines

Abstract

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′-azobis-isobutyronitrile in the presence of a large excess of amines gave good yields of the corresponding α-methylene amides. © 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.