“Release and catch” catalysis by tungstate species for the oxidative cleavage of olefins
The oxidative cleavage of olefins produces valuable carbonyl compounds, and thus, the development of green catalytic methods using H2O2 as an oxidant is highly desired. In this work, we have successfully developed an efficient catalytic system for the oxidative cleavage of olefins and related compounds using H2O2. In the presence of tungstate species supported on zinc-modified tin dioxide (W/Zn–SnO2), the oxidative cleavage of 1-methyl-1-cyclohexene proceeds efficiently through multistep reaction pathways involving oxygenation, hydrolysis, perhydrolysis, and isomerization reactions. In this reaction system, active peroxotungstate species, generated by the reaction of the supported tungstate species with H2O2, are released into the solution during the course of the reaction. At the end of the reaction (after the complete consumption of H2O2), the released tungstate species are re-captured by the support. The W/Zn–SnO2 catalyst can be reused at least nine times for the oxidative cleavage of 1-methyl-1-cyclohexene without loss of catalytic performance and can be applied to the oxidation of various other substrate molecules.