DEOXYGENATION WITHOUT TIN

Abstract

SYNTHETIC CHEMISTS LOOKing to replace hydroxy groups with hydrqgen atoms can now do so without using toxic organotin hydride reagents, thanks to a new deoxygenation procedure for alcohols. The reaction, discovered in chemistry professor John L. Wood's lab at Yale University uses trialkylborane-water complexes as an alternative to the traditional tin reagents ( J. Am. Chem.Soc. 2005 , 127 ,12513). Although it's been around for 30 years, the Barton-McCombie deoxygenation—in which an alcohol is converted to a xanthate ester, enabling replacement of the hydroxyl with a hydrogen atom via a radical process—remains one of the most useful reactions in an organic chemist's arsenal. But the organotin hydride reagents that serve as the reaction's hydrogen source are both inconvenient and unpleasant to use. They are toxic, expensive, smelly, and difficult to separate from the reaction products, Wood explains. Even so, Wood wasn't trying to develop a new deoxygenation process when he made his discovery Rather, he and ...