Vanadium-Catalyzed Enantioselective Epoxidation of Allylic Alcohols
W. Zhang, A. Basak, Y. Kosugi, Y. Hoshino, H. Yamamoto*
University of Chicago, USA
21 September 2005 (online)
Vanadium-catalyzed epoxidation of allylic alcohols is reported in moderate to excellent yields with excellent ee’s. This catalytic process features robust conditions for easy operation and requires relatively low catalyst loading (1 mol%) without the exclusion of moisture and air. Although the reactions usually were performed at -20 °C, it is possible to use room temperature without significant erosion of the ee. Under this catalyst system, challenging substrates such as Z-allylic alcohols proceeded relatively well. Kinetic resolution of a racemic secondary allylic alcohol was achieved at 51% conversion to give the product in 93% ee and the unreacted starting material in 85% ee.