Biocatalytic Routes to Optically Active Amines

Optically active amines and amino acids play an important role in the pharmaceutical, agrochemical, and chemical industries. They are frequently used as synthons for the preparation of various pharmaceutically active substances and agrochemicals, but also as resolving agents to obtain chiral carboxylic acids. Consequently, there is a need for efficient methods to obtain the desired enantiomer of a given target structure in optically pure form. Beside a range of chemical methods using for example, asymmetric synthesis with transition metal catalysts, enzymes represent a useful alternative to access this important class of compounds. This review covers biocatalytic approaches using hydrolases (i.e. lipases, amidases), monoamine oxidase and other enzymes. Special focus is given on the application of ω‐transaminases with emphasis on concepts to allow efficient asymmetric synthesis starting from prostereogenic ketones. Various enzymatic approaches for the synthesis of optically active amines are reviewed, including the use of lipases for kinetic resolution, monoamine oxidases for deracemization, and transaminases for both kinetic resolution and asymmetric synthesis (see Scheme). Limitations, such as substrate and product inhibition, can be overcome by combination with additional enzymes.