2,3-Arylacylation of allenes through synergetic catalysis of palladium and N-heterocyclic carbene

An unprecedented 2,3-arylacylation reaction of allenes with aryl iodides and aldehydes was developed by resorting to Pd/NHC synergetic catalysis. It's the first time that allene was introduced into transition metal and NHC synergetic catalysis, which demonstrated a versatile three-component reaction pattern, thus enabling two C-C bonds forged regioselectively in the reaction. The important reaction intermediates were successfully captured and characterized by HRMS analysis, and the migrative insertion of allene to the Ph-Pd species was identified as the reaction rate-limiting step by kinetic experiments.