Gold-catalyzed heterocycle synthesis using homopropargylic ethers as latent electrophiles

reaction: see text] Homopropargylic ethers with pendent nucleophiles, when subjected to Au catalysts in aqueous solvent, provide heterocyclic ketones. The reactions are efficient, tolerant of functionality and ambient atmosphere, and operationally simple. Diastereoselectivity can be predicted on the basis of product thermodynamics. This process demonstrates the viability of homopropargylic ethers to serve as latent electrophiles that can be unraveled under highly selective conditions to promote heterocycle formation through nucleophilic additions to alpha,beta-unsaturated ketones.