| Abstract
| - Benzylic, allylic, and aliphatic alcohols are oxidized to aldehydes and ketones in a reaction catalyzedby Keggin-type polyoxomolybdates, PVxMo(12-x)O40-(3+x) (x = 0, 2), with DMSO as a solvent. Theoxidation of benzylic alcohols is quantitative within hours and selective, whereas that of allylicalcohols is less selective. Oxidation of aliphatic alcohols is slower but selective. Further mechanisticstudies revealed that, for H3PMo12O40 as a catalyst and benzylic alcohols as substrates, the sulfoxideis in fact an oxygen donor in the reaction. Postulated reaction steps as determined from isotope-labeling experiments, kinetic isotope effects, and Hammett plots include (a) sulfoxide activationby complexation to the polyoxometalate and (b) oxygen transfer from the activated sulfoxide andelimination of water from the alcohol. The mechanism is supported by the reaction kinetics.
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