Ruthenium-Catalyzed Oxidative Transformation of Alcohols and Aldehydes to Esters and Lactones

Article abstract of DOI:10.1021/jo00228a032

Primary alcohols undergo oxidative condensation upon treatment with RuH2(PPh3)4 catalyst to give esters and molecular hydrogen.Similarly, 1,4- and 1,5-diols can be converted into the corresponding γ- and δ-lactones, respectively.The lactonization is greatly enhanced by accepting hydrogen with an appropriate hydrogen acceptor such as acetone.Primary alcohols are oxidized chemoselectively in the presence of secondary alcohols to give the corresponding lactones.These reactions are operationally simple and highly efficient for synthesis of esters and lactones from alcohols.The principle of the oxidative condensation of alcohols can be extended to ester formation from aldehydes and alcohols.The ruthenium-catalyzed reaction of aldehydes with water gives esters, while the same reaction in the presence of a hydrogen acceptor gives carboxylic acids.The key step of these reactions is the oxidative addition of ruthenium into the OH bonds of alcohols and subsequent β-elimination of (RuH) species to give the corresponding carbonyl compounds.