Efficient Biocatalytic Reductive Aminations by Extending the Imine Reductase Toolbox

Abstract Chiral secondary and tertiary amines are ubiquitous in pharmaceutical, fine, and specialty chemicals, but their synthesis typically suffers from significant sustainability and selectivity challenges. Biocatalytic alternatives, such as enzyme‐catalyzed reductive amination, offer several advantages over traditional chemistry, but industrial applicability has not yet been demonstrated. Herein, we report the use of cell lysates expressing imine reductases operating at 1:1 stoichiometry for a variety of amines and carbonyls. A collection of biocatalysts with diversity in coverage of small molecules and direct industrial applicability is presented.