Palladium-catalyzed intermolecular allenylation reactions of 2,3-disubstituted indoles and allenyl carbonate.

A palladium-catalyzed intermolecular allenylation of non-strained 2,3-disubstituted indoles and allenyl carbonate has been developed, providing convenient access to indolenines bearing an allene unit by taking advantage of the C-3 nucleophilicity of indoles. Decent yields and good functional group tolerance have been achieved with diverse indoles under mild conditions. Gram-scale reaction and various synthetic transformations have been demonstrated.