Potassium 2-oxo-3-enoates as Effective and Versatile Surrogates for alpha, beta-Unsaturated Aldehydes in NHC-Catalyzed Asymmetric Reactions

Potassium 2-oxo-3-enoates, which are readily prepared at scale and easily stored, have been found to be effective and versatile surrogates for alpha, beta-unsaturated aldehydes in NHC-catalyzed asymmetric reactions. Promoted by chiral N-heterocyclic carbenes combined with LiCl, these easy-to-handle solid salts could release of CO2 and then undergo asymmetric reactions via homoenolate and alpha, beta-unsaturated acyl azolium intermediate. The reactions have broad substrate scopes with high enantioselectivities.