Organocatalytic Hyciroacylation of Unactivated Alkenes

摘要

Aldehyde umpolung, the inversion of the electrophilicity of the carbonyl group into a nucleophile, has its origins in Wohler and Liebig's 1832 paper describing the cyanide-catalyzed benzoin reaction. One hundred years later, Ukai et al. demonstrated the same transformation using thiazolium precatalysts in the presence of base. In 1958, Breslow first proposed the currently accepted mechanism of this transformation, building on Lapworth's mechanism for the cyanide-catalyzed benzoin reaction. In 1974, Stetter showed that Michael acceptors may also be used as electrophiles for the acyl anion equivalent. With the advent of N-heterocyclic carbenes, there has been a huge upsurge in reactivity associated with these systems, with chiral catalysts, novel reactions, new modes of reactivity and their applications to synthesis all making an appearance.