Reductive Functionalization of Carboxamides: A Recent Update

Carboxamides including lactams are readily available and bench-stable chemical feedstock, and thus their use in chemical synthesis for production of valuable compounds would be an attractive choice in various synthetic endeavors. This review highlights and discusses recent advances on deoxygenative reductive functionalization of carboxamides for the synthesis of α-branched amines, that is initiated by controlled single hydride delivery to the amide carbonyl group and terminated by downstream functionalization of the iminium intermediates. The protocols are categorized based on the types of the reduction processes including those with aluminum hydrides, the Schwartz's reagent, transition metal-catalyzed/mediated hydrosilylation, and sodium hydride-iodide composite.