Taming the carbamoyl radical for selective hydrocarbamidation of alkynes via metallaphotoredox catalysis

Abstract

The direct addition of an amide group across unsaturated C–C bonds remains a persistent challenge in chemical transformations. Although nickel-catalyzed hydrocarbamoylation and hydroamidation reactions of alkynes have been developed under thermal conditions, these protocols typically require formamide and isocyanate as amide surrogates, which restricts their utility due to the limited range of compatible amide coupling partners. Herein, we probed a synthetically mild and efficient hydrocarbamidation of alkynes using carbamoyl chlorides enabled by Ir-photoredox/Ni catalysis. This protocol uniquely integrates the reactivity of silane in photocatalytic radical generation from carbamoyl chlorides and the efficient merging of the carbamoyl radical with the nickel catalytic cycle. The method exhibits substrate scope encompassing various alkynes and a diverse array of carbamoyl chlorides, and delivers the corresponding acrylamides with synthetically useful yields. Owing to its operational simplicity, scalability, and mild reaction conditions, this strategy provides a valuable platform for late-stage functionalization of drug-like molecules and synthesis of complex acrylamide scaffolds, which are widely found in pharmacophores and materials-science-related compounds.