Expanding dynamic kinetic protocols: transaminase-catalyzed synthesis of α-substituted β-amino ester derivatives

Several alpha-alkylated beta-amino esters have been obtained via DKR processes employing a kit of transaminases and isopropylamine as an amino donor in aqueous medium under mild conditions. Thus, while acyclic alpha-alkyl-beta-keto esters afforded excellent conversions and enantioselectivities, although usually low diastereoselectivities, using more constrained cyclic beta-keto esters high to excellent inductions were obtained.