Biocatalysis offers an alternative approach to conventional chemical processes for the production of single-isomer chiral drugs. Lipases are one of the most used enzymes in the synthesis of enantiomerically pure intermediates. The use of this type of enzyme is mainly due to the characteristics of their regio-, chemo- and enantioselectivity in the resolution process of racemates, without the use of cofactors. Moreover, this class of enzymes has generally excellent stability in the presence of organic solvents, facilitating the solubility of the organic substrate to be modified. Further improvements and new applications have been achieved in the syntheses of biologically active compounds catalyzed by lipases. This review critically reports and discusses examples from recent literature (2007 to mid-2015), concerning the synthesis of enantiomerically pure active pharmaceutical ingredients (APIs) and their intermediates in which the key step involves the action of a lipase.

The continuous flow synthesis of a series of amines was successfully achieved by exploiting the enhanced stability and broad substrate scope of an immobilised transaminase from Halomonas elongata (HEWT). A series of substrates were tested in flow reactors and transformed into the corresponding amines in good to excellent yields. The process was implemented with an integrated in-line purification step for the recovery of the pure amines.