Electron Transfer Reduction of Carboxylic Acids Using SmI2-H2O-Et3N

The first general method for efficient electron transfer reduction of carboxylic acids has been developed. The protocol using SmI2-H2O-Et3N allows for reduction of a variety of carboxylic acids in excellent yields and provides an attractive alternative to processes mediated by reactive alkali metals, lithium aluminum hydride, and boron hydrides. Of broader significance, the method allows acyl radical equivalents to be generated from carboxylic acids under mild reaction conditions.