Electroenzymatic Cascade for Chiral Hydroxylation of C–H Bond Using In Situ H2O2 Generation

Abstract Unspecific peroxygenase (UPO) catalyzes selective oxyfunctionalization of C–H bonds using H2O2 but suffers from enzyme instability and substrate solubility issues. To address these challenges, a cobalt and nitrogen co-doped carbon nanotubes electrocatalyst with two-electron oxygen reduction performance was developed to electrocatalytically generate H2O2 in situ to avoid the damage from adscititious H2O2. This approach maintains the H2O2 concentration in the reaction system to balance the reactivity and oxidative inactivation of UPO. Meanwhile, a covalent organic framework (COF, TpTa) with good biocompatibility was selected as the carrier to prepare AaeUPO@TpTa immobilized enzymes, enhancing enzyme stability and substrate enrichment. By integrating the in situ H2O2 generation system via electrocatalysis with immobilized enzyme catalysis, and using 4-ethylbenzoic acid as a model substrate, the reaction achieved a 99.1% yield of 4-(1-hydroxyethyl)benzoic acid after 16 h, with broad substrate applicability and excellent enantioselectivity (94–99% ee). The constructed electroenzymatic cascade catalysis system enables efficient C–H bond hydroxylation.