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Enzymatic cascade synthesis of valuable chiral pharmaceutical intermediates has attracted attention owing to efficient and environmentally friendly routes. Currently, the synthesis of a key precursor of sacubitril valsartan sodium hydrate LCZ696 proceeds viaseparate steps of metal-catalyzed asymmetric hydrogenation and enzymatic transamination. Herein, we present a one-pot enzymatic cascade strategy for the construction of two chiral centers without the separation of intermediates. Upon enzyme discovery and identification, an ene-reductase GoER from Gluconobacter oxydanswas incorporated in one-pot cascades with enzymatic transamination. Three different biocatalytic cascades were developed, utilizing whole cells co-expressing two enzymes, a mixture of whole cells expressing a single enzyme, and purified enzymes, affording a key intermediate in up to 87% yield and 99% de. More importantly, the scale-up preparation afforded 68.5% isolated yield with excellent diastereoselectivity. This study not only offers a sustainable alternative but also paves the way for the scalable production of a key sacubitril precursor.

Chiral amino alcohols are essential building blocks for the pharmaceutical industry, and are widely present in natural and synthetic bioactive compounds. Amine dehydrogenases (AmDHs) can asymmetrically reduce prochiral ketones with low-cost ammonia to chiral amines and water as by-products, using NAD(P)H as a cofactor under mild conditions, but hydroxy ketones with formation of chiral hydroxy amines have rarely been investigated. In this study, six new bacterial AmDHs derived from amino acid dehydrogenases (AADHs) were identified by data mining, and five out of the six enzymes were able to efficiently reduce 1-hydroxybutan-2-one (1a) to (S)-2-aminobutan-1-ol ((S)-2a) with 19–99% conversions and 99% ee. The five AmDHs were purified and biochemically characterized for reductive amination activity towards substrate 1awith the optimal pH at 8.5 or 9.0 and the optimal temperature at 45 °C, 50 °C or 55 °C, and provided reductive amination of a broad range of prochiral α-hydroxy ketones, and even of a model β-hydroxy ketone leading to β-hydroxy amine with 99% ee. Our study expands the toolbox of AmDHs in the synthesis of chiral amino alcohols.