NHC-catalyzed β-specific addition of N-based nucleophiles to allenoates

N-Heterocyclic carbene (NHC) catalyzed regiospecific beta-additions of nitrogen-containing nucleophiles including nitrogenous heterocycles and trifluoromethylated acylhydrazone to allenoates were accomplished under mild reaction conditions, harnessing NHC as a Lewis base to furnish branchedN-alkyl compounds in moderate to good yields with highE/Zselectivity and broad substrate scope. DFT calculations on the possible reaction mechanisms show that the beta-addition pathway is more energetically favourable than the gamma-addition pathway, which is in agreement with the experimental observations.