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.