Solvent engineering: an effective tool to direct chemoselectivity in a lipase-catalyzed Michael addition

A solvent engineering strategy was implemented in order to control the chemoselectivity in a lipase-catalyzed Michael addition reaction. This strategy was revealed as a high-effective tool for the selective synthesis of Michael adduct 3 or aminolysis product 4 from benzylamine 1 and methyl crotonate 2. Chemoselectivity of the enzymatic process was elucidated in terms of polarity of the medium, hence, adduct 3 was preferentially accumulated in hydrophobic medium, whereas in polar solvents the amide 4 was preferentially formed. (C) 2008 Elsevier Ltd. All rights reserved.