Palladium-Catalyzed α,β-Dehydrogenation of Esters and Nitriles
摘要:
A highly practical and general palladium-catalyzed methodology for the alpha,beta-dehydrogenation of esters and nitriles is repotted. Generation of a zinc enolate or (cyanoalkyl)zinc species followed by the addition of an allyl oxidant and a palladium catalyst results in synthetically useful yields of alpha,beta-unsaturated esters, lactones, and nitriles. Preliminary mechanistic investigations are consistent with reversible beta-hydride elimination and turnover-limiting, propene-forming reductive elimination.