Efficient, regioselective epoxidation of dienes with hydrogen peroxide catalyzed by [γ-SiW10O34(H2O)2]4-

A divacant, lacunary, Keggin-type silicotungstate, [gamma-SiW10O34(H2O)(2)](4-), exhibits high catalytic performance for the epoxidation of various nonconjugated dienes using hydrogen peroxide under mild conditions, high regioselectivity to the more accessible double bonds, and high efficiency of hydrogen peroxide utilization. The high regioselectivity for the [gamma-SiW10O34(H2O)(2)](4-)-catalyzed epoxidation would be caused by the steric hindrance of the active site. (C) 2004 Elsevier Inc. All rights reserved.