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.
Jie Chen, Zhuoting Peng, Xiaolong Gao et al.· ACS Catalysis· 0 citations
Epilactose is a promising functional disaccharide, but its biomanufacturing is limited by insufficient enzyme activity, poor thermostability, and costly catalyst preparation. We first used the REME platform to computationally evaluate candidate enzymes. Among them, cellobiose 2-epimerase from Caldicellulosiruptor saccharolyticus (CsCE) showed the highest epilactose synthesis activity. We therefore developed an integrated strategy combining computational design, SpyTag/SpyCatcher-mediated cyclization, and ethanol-permeabilized whole-cell catalysis. By combining enzyme ligand binding energy analysis, protein stability prediction, and catalytic constant prediction, the V52N variant was obtained. Its epilactose synthesis activity was 3.45 times that of the wild type, while lactulose formation was reduced to 14.8% of the wild-type level. Cyclized CCT increased the optimum temperature to 80 °C and extended the half-life at 85 °C by 5.52-fold. The optimized whole-cell process produced 65.81 g/L epilactose from 200 g/L lactose within 20 min, corresponding to 32.90% conversion. This strategy provides a practical route for efficient epilactose biomanufacturing.
