Catalytic oxidation of alcohols to esters with Ru 3(CO) 12

Abstract

Ru 3(CO) 12 is an efficient homogeneous catalyst precursor for the conversion 2RCH 2OH → RCO 2CH 2R. With aliphatic primary alcohols and benzylic alcohols yields and selectivities of ca. 90% are obtained. The reaction requires a hydrogen acceptor molecule; triple bonds and activated double bonds, as well as ketones and aldehydes, function as H-acceptors. The reaction proceeds in two steps, with an aldehyde intermediate which subsequently oxidatively couples with an alcohol to generate an ester. In most cases the aldehyde is present in a steady state concentration implying the presence of an equilibrium system. A disproportionation alcohol aldehyde is a component of the above system. A catalytically active intermediate complex, Ru 2(CO) 6(Ph 2C 2), was isolated when Ph 2C 2 was used as an acceptor.