A green and sustainable phosphine-free NHC-ruthenium catalyst for selective oxidation of alcohols to carboxylic acids in water.

In this work, we present a new catalytic system for the selective dehydrogenative oxidation of primary alcohols to carboxylic acids using a phosphine-free NHC-ruthenium catalyst in water under mild reaction conditions. With this catalytic system, a variety of primary alcohols have been converted to carboxylic acids respectively, in aqueous media, without using any additional oxidant; the only side product in this reaction is molecular hydrogen. This novel synthetic protocol is applied for direct oxidation of biologically active monosaccharides and polymers with primary alcohol groups in the side chain. The use of water as a solvent and oxygen donor as well as the absence of any toxic oxidizing agent make this atom economical reaction interesting from an environmental point of view.