Biocatalytic Dynamic Kinetic Resolutions Enable Enantiodivergent Access to Axially Chiral Biaryl Dimethanols via Transient Seven-Membered Lactols
Axially chiral biaryl dimethanols are ubiquitous and multifunctional intermediates for the synthesis of valuable atropisomeric molecules in advanced materials, drugs, natural products, and organocatalysts. Despite their broad synthetic utility, direct enantiodivergent catalytic access to this specific class of compounds remains largely unexplored, particularly in biocatalysis. Herein, we report a biocatalytic platform for enantiodivergent and atroposelective dynamic kinetic carbonyl reduction via transient seven-membered cyclic lactol intermediates. These engineered alcohol dehydrogenase (ADH)-driven transformations deliver up to 99% yield and enantioselectivity (>99:1 e.r. and < 1:99 e.r). This strategy demonstrates broad substrate compatibility, extending even to complementary “flipped” substrate series. Furthermore, the protocol is readily scalable to gram quantities and accommodates diverse downstream derivatizations. Mechanistic experiments and theoretical calculations delineate the pathway and illuminate the origin of enzymatic stereocontrol.