This review summarizes recent developments for the epoxidn. of olefins with hydrogen peroxide catalyzed by polyoxometalates. The versatility, accessibility, and tunability of polyoxometalates open up the development of effective epoxidn. systems. Polyoxometalates for H2O2-based epoxidn. can be classified into two groups according to the structural and mechanistic aspects: (i) catalyst precursors of peroxo-tungstate or peroxo-molybdate species and (ii) oxidatively and hydrolytically stable transition-metal-substituted polyoxometalates. In addn., we describe our recent studies on the silicotungstate compd., [ﾎｳ-SiW10O34(H2O)2]4- (I*), synthesized by protonation of divacant lacunary Keggin-type [ﾎｳ-SiW10O36]8-. The tetra-n-butylammonium salt deriv. of I* (TBA-I*) exhibits high catalytic activity in the epoxidn. of various olefins including non-reactive terminal olefins such as propylene with hydrogen peroxide under mild conditions. [on SciFinder(R)]
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