Atroposelective Synthesis of 2-(Quinolin-8-yl)benzyl Alcohols by Biocatalytic Dynamic Kinetic Resolutions

Abstract

A highly enantioselective biocatalytic dynamic kinetic resolution (DKR) of 2-(quinoline-8-yl) 3-methylbenzaldehydes and 1-naphthaldehydes is described. The reaction proceeds by atroposelective carbonyl reduction catalyzed by commercial ketoreductases (KREDs), generally reaching high conversions and excellent enantiomeric excesses. Both atropoisomers of the final alcohols can be obtained by a proper selection of the biocatalyst. The DKR strategy relies in the racemization of the stereogenic axis that takes place thanks to a transient Lewis acid-base interaction (LABI) between the nitrogen in the quinoline and the carbonyl group.