Stereo-complementary bioreduction of saturated N-heterocyclic ketones

The asymmetric bioreduction of several saturated N-heterocyclic ketones is demonstrated in a stereo-complementary fashion using the ketoreductases READH and ChKRED20 for the production of (S)- and (R)-alcohols, respectively. The reaction accepts substrates with a five-, six- or seven-membered ring, and exhibits excellent stereoselectivity when using 2-propanol as both the ultimate reducing agent and cosolvent, achieve >99% ee in the majority of cases for both enantiomers.