| Abstract
| - A new procedure for the oxidation (dehydrogenation) of primary andsecondary alcohols employingZr(O-t-Bu)4 orZr(O-n-Pr)4/tert-butylhydroperoxide/3 Å molecular sieves is presented.Secondaryalcoholsif not severely sterically hinderedare usually convertedquantitatively to the corresponding ketones. Esters or acids can be byproducts in the reactionof primary alcohols. However,the aldehydes are obtained in good yield by lowering the reactiontemperature, decreasing theamount of TBHP or replacing TBHP by cumene hydroperoxide (CHP), and/orexchanging the catalystZr(O-t-Bu)4 byZr(O-n-Pr)4 or silica gel-supportedZr(OR)x. A remarkable selectivity ofequatorialalcohol groups (e.g., 11 and 13) is observed incontrast to chromium(VI)-based oxidations.Stronglychelating substrates such as furfuryl alcohol (18) or1,2-diol 25 that prevent hydride transfer inthe six-membered transition state A are notconverted.
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