Use of a semihollow-shaped triethynylphosphane ligand for efficient formation of six- and seven-membered ring ethers through gold(I)-catalyzed cyclization of hydroxy-tethered propargylic esters

Article abstract of DOI:10.1002/adsc.201200949

The formation of six- and seven-membered ring ethers from hydroxy-tethered propargylic esters was efficiently catalyzed by a cationic gold(I) complex with a semihollow-shaped triethynylphosphane ligand. This gold catalysis showed a tolerance toward the reactions of primary, secondary, and tertiary alcohol substrates with various substitution patterns. A sterically congested 2,2,6,6-tetraalkyl-substituted tetrahydropyran derivative as well as 6,6- and 7,6-fused bicyclic diethers were obtained in useful yields. In addition, the gold catalysis was applicable to the reaction of a sulfonamide-tethered propargylic ester to give a piperidine derivative. Copyright