Au/Ag-Catalyzed Intramolecular Ring-Opening of Vinylidene-cyclopropanes (VDCPs): An Easy Access to Functional Tetrahydropyrans
摘要:
An intramolecular ring-opening of vinylidenecyclopropanes (VDCPs) tethered with alcohol chains has been established. A series of transition metal catalysts and their combinations have been screened under mild conditions, and a cocatalyst system consisting of [(Ph3PAu)(3)O]BF4 (4 mol %) and AgOTf (4 mol %) was found to catalyze the reaction to completion within 10-30 min in 1,4-dioxane at 60 degrees C to give allene-functionalized tetrahydropyrans.