Gold(I)-Catalyzed 1,4- and/or 1,5-Heteroaryl Migration Reactions through Regiocontrolled Cyclizations

Gold(I)‐catalyzed regioselective cycloisomerizations of furan‐ynes have been described. The reaction provides a concise access to stereodefined trisubstituted alkenes by endo cyclization with concomitant 1,5‐migration of the furanyl group in the presence of unactivated 3 Å molecular sieves. In the absence of molecular sieves, indene products are generated by exo cyclization, followed by 1,4‐furanyl migration/cyclization. The scope for 1,5‐migrations can be extended to other heterocycles, such as benzofurans, thiophenes, and pyrroles. Migrate to complex products: Gold(I)‐catalyzed regioselective cycloisomerizations of furan‐ynes have been developed. In the presence of unactivated 3 Å molecular sieves, trisubstituted alkenes were provided stereoselectively by endo cyclization with concomitant 1,5‐migration of the furanyl group. In the absence of molecular sieves, indene products were generated by exo cyclization followed by 1,4‐furanyl migration/cyclization (see scheme).