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

摘要

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 angstrom 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.