Double diastereoselection in aldol reactions mediated by dicyclohexylchloroborane between L-erythrulose derivatives and chiral aldehydes. The Felkin-Anh versus cornforth dichotomy

Matched and mismatched diastereoselections are observed in aldol reactions of the B, B-dicyclohexylboron enolate of a protected L-erythrulose derivative with a range of chiral aldehydes. Within the Felkin-Anh paradigm, the stereochemical outcome of reactions with alpha-methyl aldehydes can be explained efficiently.