Zinc‐Catalyzed Enantiospecific sp³–sp³ Cross‐Coupling of α‐Hydroxy Ester Triflates with Grignard Reagents

Zinc chloride does the trick and efficiently catalyzes the enantiospecific cross-coupling of α-hydroxy ester triflates with Grignard reagents under mild conditions. Enantiopure α-hydroxy esters are directly available from the chiral pool or by diazotization of α-amino acids. Substantial variations in both reacting partners are tolerated making this methodology an attractive alternative to enolate alkylation featuring a reversal of polarity.