Dioxomolybdenum(VI) compounds with alpha-amino acid donor ligands as catalytic precursors for the selective oxyfunctionalization of olefins

A series of cis-dioxomolybdenum(VI) -amino acid containing compounds I–V has been investigatedas potential catalyst precursors for the mild and selective oxyfunctionalization of conjugated or uncon-jugated olefins like styrene, -methylstyrene, cis--methylstyrene, cyclohexene and cyclooctene, usingtert-butyl hydroperoxide (TBHP) as main oxidant. All the I–V complexes behaved as active heterogeneousand recyclable catalysts, showing good to quantitative conversion values of the substrate. In all cases,high selectivity toward the corresponding epoxide formation was detected. No substantial difference interms of efficiency has been observed among the different catalysts I–V, thus confirming that the dif-ferent nature of the amino acidic side-chain does not strictly affect the catalytic process. Insights intomechanistic details and reaction free energy profile of catalytic oxidations by means of quantum chemicalcalculations have been discussed.