A Cascade Synthesis of Hetero-arylated Triarylmethanes Through a Double 5-endo-dig Cyclization Sequence

A sequential two-step method for the synthesis of hetero-arylated triarylmethanes through a Ag-catalyzed sequential double cyclization-nucleophilic addition cascade is described. This methodology basically involves an initial 5-endo-dig cyclization of o-alkynyl anilines to provide 2-substituted indole derivatives, which then react with 2-(2-enynyl)-pyridines to afford indolizine-containing unsymmetrical triarylmethanes through another 5-endo-dig cyclization.