Au/Ag-Catalyzed Intramolecular Ring-Opening of Vinylidene-cyclopropanes (VDCPs): An Easy Access to Functional Tetrahydropyrans
作者:Wei Li、Wei Yuan、Surech Pindi、Min Shi、Guigen Li
DOI:10.1021/ol902832s
日期:2010.3.5
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.
Halogenation Reagents Initiating Ring Opening of Vinylidenecyclopropanes: Easy Access to Halogenated Tetrahydropyrans
作者:Min Shi、Wei Yuan
DOI:10.1055/s-0030-1259715
日期:2011.4
A novel synthetic protocol that uses halogenation reagents (NBS, NIS and selectfluor) to initiate intramolecular ring-opening reactions of diarylvinylidenecyclopropanes (VDCPs) connected to alcohol-bearing chains has been developed. The approach provides a variety of halogenated tetrahydropyran derivatives in moderate to good yields under mild conditions. Plausible reaction mechanisms are proposed on the basis of previous literature and the substrate scope has been carefully examined.