Yb(III)-Catalyzed Asymmetric Aldol-Tishchenko Reaction

Significance

An Yb-catalyzed asymmetric tandem aldol-Tishchenko reaction between a ketone and an aromatic aldehyde afforded a mixture of monoprotected anti-1,3-diols in moderate to good yield using a chiral ephedrine derivative as ligand. Three contiguous stereogenic centers were generated with good enantioselectivity and excellent diastereoselectivity in one simple step. A range of steric and electronic functionalities was tolerated. Although in most cases the products were produced as an equilibrium mixture of 1-O or 3-O esters, both isomers gave the same enantio-enriched anti-1,3-diol upon basic hydrolysis. Since the origin of the enantioselectivity is the C-C bond formation in the aldol reaction, the enantio­selectivities of both the 1-O or 3-O ester isomers are the same.