Cu‐Catalyzed Tandem Oxidation‐Intramolecular Cannizzaro Reaction of Biorenewables and Bioactive Molecules

Abstract A tandem Cu‐catalyzed oxidation‐intramolecular Cannizzaro reaction leading to bioactive α ‐hydroxyesters from α ‐hydroxyketones is reported. The process uses oxygen as a sole oxidant to achieve the formation of glyoxals, which are efficiently converted in situ to important α ‐hydroxyesters. The mechanistic insights are provided by isotopic labeling and supported by DFT calculations. The transformation proved a robust synthetic tool to achieve the synthesis of human metabolites and hydroxyl esters of various biologically active steroid derivatives.