Rational design of short-chain dehydrogenase/reductase for enantio-complementary synthesis of chiral 1,2-diols by successive hydroxymethylation and reduction of aldehydes.

Enantiopure 1,2-diols are widely used in the production of pharmaceuticals, cosmetics, and functional materials as essential building blocks or bioactive compounds. Nevertheless, developing a mild, efficient and environmentally friendly biocatalytic route for manufacturing enantiopure 1,2-diols from simple substrate remains a challenge. Here, we designed and realized a step-wise biocatalytic cascade to access chiral 1,2-diols starting from aromatic aldehyde and formaldehyde enabled by a newly mined benzaldehyde lyase from Sphingobium sp. combined with a pair of tailored-made short-chain dehydrogenase/reductase from Pseudomonas monteilii (PmSDR-MuR and PmSDR-MuS) capable of producing (R)- and (S)-1-phenylethane-1,2-diol with 99% ee. The planned biocatalytic cascade could synthesize a series of enantiopure 1,2-diols with a broad scope (16 samples), excellent conversions (94%-99%), and outstanding enantioselectivity (up to 99% ee), making it an effective technique for producing chiral 1,2-diols in a more environmentally friendly and sustainable manner.