Ru-MACHO-Catalyzed Highly Chemoselective Hydrogenation of α-Keto Esters to 1,2-Diols or α-Hydroxy Esters

A ruthenium pincer catalyst has been shown to be highly effective for the hydrogenation of a wide range of α-keto esters, affording either diols or hydroxy esters depending on the choice of reaction conditions. Strong base, high temperature, and pressure favor the formation of diols whilst the opposite is true for the hydroxy esters.