Harnessing Nucleophilicity of Allenol Ester with <i>p-</i>Quinone Methides via Gold Catalysis: Application to the Synthesis of Diarylmethine-Substituted Enones

A gold­(I)-catalyzed protocol for intermolecular 1,6-conjugate addition of nucleophilic allenol ester generated in situ through [3,3]-sigmatropic rearrangement with <i>p</i>-quinone methides (<i>p</i>-QMs) has been developed. The gold catalyst plays a dual role by the π-acid-triggered activation of alkynes and at the same time as a Lewis acid for activation of <i>p</i>-QMs toward nucleophilic attack. This method enables rapid access to a wide range of densely functionalized diarylmethine-substituted enones, a Morita-Baylis-Hillman (MBH) product with high selectivity, excellent yields, and broad substrate scope.