Aerobic oxidation of benzyl alcohols by MoVI compounds

Selective and controlled aerobic oxidation of activated benzyl alcohols to the corresponding aldehydes is achieved in refluxing CH3CN using catalytic amounts of MoO2Cl2(L)(2) where L is DMSO, DMF or THF. The catalysis reactions are possible under open air in the absence of any other external co-oxidants. However, bubbling of oxygen to the reaction mixture is useful in making the catalysis reaction sustained. Both activated and deactivated varieties of a-substituted benzyl alcohols (secondary alcohols) give ketones in the same reaction conditions. The inexpensive catalyst is selective towards activated primary benzyl alcohols and also, being mild, stops the oxidation at the aldehyde stage, making it synthetically useful. Copyright (c) 2006 John Wiley & Sons, Ltd.