Metallophosphites as Umpolung Catalysts: The Enantioselective Cross Silyl Benzoin Reaction

摘要

Polarity reversal (reactivity umpolung) of functional groups is a powerful synthetic strategy that has been widely employed by organic chemists. The benzoin condensation is the archetypal catalytic reaction in which carbonyl polarity is inverted via an intermediate that functions as an acyl anion equivalent. To date, this reactivity pattern has only been realized catalytically with cyanide anion or heteroazolium carbenes. Herein, we introduce metallophosphites as a new class of catalyst capable of achieving this challenging bond construction and concurrently describe the development of chiral phosphites that facilitate nonenzymatic asymmetric cross benzoin reactions (eq 1).