Photocatalytic/Bio-Catalytic Coupled Photoreactor for Asymmetric Reduction of Acetophenones Under Solar Light.

Chiral alcohols are significant organic compounds that serve as key building blocks for the synthesis of many pharmaceuticals and fine chemicals. The asymmetric reduction of prochiral ketones via coupled photocatalytic-biocatalytic systems has emerged as one of the most promising and sustainable routes. In this study, we report an aminomethyl-polystyrene resin coupled eosin-B (PSR@Eb) solar light harvesting photocatalyst which is synthesized via acid-amine coupling approach. Notably,  the as prepared PSR@Eb photocatalyst exhibit an excellent photocatalytic activity for the NADPH regeneration and asymmetric reduction of acetophenones to a chiral alcohol (1-phenyl ethanol). Additionally, this asymmetric reduction proceeds under mild and environmentally benign conditions through alcohol dehydrogenase (ADH)-mediated catalysis, eliminating the need for stoichiometric metal-based reductants. This coupled photocatalytic-biocatalytic photoreactors offers a sustainable route for the synthesis of optically enriched alcohols, which are of significant application to the pharmaceutical, flavor and fragrance, and agrochemical industries.