Ag(II)-Catalyzed Asymmetric Mukaiyama Aldol Reaction of α-Keto Esters

Significance

Using a AgF₂/pyridyl Schiff base dipeptide catalyst system, a variety of α-keto esters underwent the Mukaiyama aldol reaction with silyl enol ethers to afford chiral tertiary alcohols with moderate to very high levels of enantio­selectivity. When the keto ester contained a remote reactive functional group, the products could be elaborated to chiral heterocyclic compounds (see scheme). The main advantage of this method over similar, Cu-based catalysts, is that oxygen does not need to be excluded from the ­reaction vessel, as Ag catalysts are not prone to oxidation.