Hydrogen-Borrowing Alcohol Bioamination with Coimmobilized Dehydrogenases

Abstract

The amination of alcohols is an important transformation in chemistry. The redox-neutral (i.e., hydrogen-borrowing) asymmetric amination of alcohols is enabled by the combination of an alcohol dehydrogenase (ADH) with an amine dehydrogenase (AmDH). In this work, we enhanced the efficiency of hydrogen-borrowing biocatalytic amination by co-immobilizing both dehydrogenases on controlled porosity glass FeIII ion-affinity beads. The recyclability of the dual-enzyme system was demonstrated (5 cycles) with total turnover numbers of >4000 and >1000 for ADH and AmDH, respectively. A set of (S)-configured alcohol substrates was aminated with up to 95 % conversion and >99 % ee (R). Preparative-scale amination of (S)-phenylpropan-2-ol resulted in 90 % conversion and 80 % yield of the product in 24 h.