Gold(I)-catalyzed cyclization of o-(alkynyl)styrene ether mediated by MeOH for the construction of 2-aryl-1H-indene acetal

A facile and highly efficient methodology was developed to synthesize the functional indene acetal through the cyclization of o-(alkynyl)styrene ether catalyzed by the Au(I) in the presence of MeOH. The 2-aryl-1H-indene acetals were obtained in excellent yields and could be easily transformed to indene aldehyde. Notably, the MeOH played a dual role, which includes acting as both a nucleophilic reagent and an auxiliary to mediate the cyclization of the 1,5-enyne ether.