B(C6F5)3-Catalyzed cyclization of alkynes: direct synthesis of 3-silyl heterocyclic compounds

An efficient one-pot strategy for easy access to 3-silyl heterocyclic compounds was developed via a B(C6F5)3-catalyzed cycloaddition reaction of o-(1-alkynyl)(thio)anisoles or o-(1-alkynyl)-N-methylaniline. In this reaction, benzenethiophene, benzofuran or indole skeletons could be constructed by an intermolecular cyclization with diphenylsilane. This protocol elicited moderate-to-good yields with metal-free reaction systems.