Lipases in beta-dipeptide synthesis in organic solvents.

A number of beta-dipeptides were prepared by two-step lipase-catalyzed reactions where N-acetylated beta-amino esters were first activated as 2,2,2-trifluoroethyl esters with Candida antarctica lipase B (CAL-B). The activated esters were then used to acylate beta-amino ester in the presence of Candida antarctica lipase A (CAL-A) in dry Et2O or i-Pr2O. [reaction: see text].