Optically pure sulfoxides are noteworthy compounds applied in a wide range of industrial fields; however, the biocatalytic deracemization of racemic sulfoxides is challenging. Herein, a high‐enantioselective methionine sulfoxide reductase A (MsrA) was combined with a low‐enantioselective styrene monooxygenase (SMO) for the cyclic deracemization of sulfoxides. Enantiopure sulfoxides were obtained in >90 % yield and with >90 % enantiomeric excess (ee) through dynamic “selective reduction and non‐selective oxidation” cycles. The cofactors of MsrA and SMO were subsequently regenerated by the cascade catalysis of three auxiliary enzymes through the consumption of low‐cost D‐glucose. Moreover, this “one‐pot, one‐step” cyclic deracemization strategy exhibited a wide substrate scope toward various aromatic, heteroaromatic, alkyl and thio‐alkyl sulfoxides. This system proposed an efficient strategy for the green synthesis of chiral sulfoxide.

Optically pure sulfoxides are noteworthy compounds that find wide applications in various industrial fields. Here we report a methionine sulfoxide reductase B (MsrB) homologue that exhibits high enantioselectivity and broad...

Optically pure sulfoxides are noteworthy compounds applied in a wide range of industrial fields; however, the biocatalytic deracemization of racemic sulfoxides is challenging. Herein, a high‐enantioselective methionine sulfoxide reductase A (MsrA) was combined with a low‐enantioselective styrene monooxygenase (SMO) for the cyclic deracemization of sulfoxides. Enantiopure sulfoxides were obtained in >90 % yield and with >90 % enantiomeric excess (ee) through dynamic “selective reduction and non‐selective oxidation” cycles. The cofactors of MsrA and SMO were subsequently regenerated by the cascade catalysis of three auxiliary enzymes through the consumption of low‐cost D‐glucose. Moreover, this “one‐pot, one‐step” cyclic deracemization strategy exhibited a wide substrate scope toward various aromatic, heteroaromatic, alkyl and thio‐alkyl sulfoxides. This system proposed an efficient strategy for the green synthesis of chiral sulfoxide.