P450DA Monooxygenase-Catalyzed\nChemoselective and\nEnantiodivergent Epoxidation of Unactivated Alkenes

While enzymatic epoxidation\nof activated olefins by P450s has been\nwell-established, chemo- and enantioselective epoxidation of unactivated\nolefins remains a formidable challenge, mainly due to the presence\nof competing hydroxylation of allylic C–H bonds. In addition,\nP450 monooxygenase-catalyzed epoxidation of olefins generally provides <i>S</i>-configured products with high enantiopurity, and examples\nof P450 enzymes demonstrating high <i>R</i>-enantioselectivity\nin epoxidation reactions remain rare. Herein, we report a chemoselective\nand enantiodivergent epoxidation of unactivated alkenes using engineered\nP450DA monooxygenases. The P450DA variants, obtained through structure-guided\ndirected evolution based on the X-ray of P450DA-WT and P450DA-M3,\nswitch the reactivity from the native hydroxylation of the allylic\nC–H bonds to epoxidation of CC bonds and exhibit superior\nchemoselectivity (up to 99% epoxidation selectivity) and enantioselectivity\n(up to >99:1 er), delivering a wide variety of versatile and enantioenriched\nepoxides. Notably, an enantiodivergent synthesis was achieved simply\nby employing different P450DA variants, leading to both enantiomers\nof the epoxide products. Various transformations of the products were\ncarried out, illustrating the synthetic utilities of the methods.\nFurthermore, molecular dockings and molecular dynamics simulations\nreveal the origin of high epoxidation selectivity and complementary\nstereoselectivity of the mutants.