Enantiodivergent Synthesis of Halohydrins by Engineering P450DA Monooxygenases

Abstract

Chiral γ-halohydrins and β-haloallyl alcohols are important building blocks for the synthesis of pharmacologically active compounds. Direct enantioselective C–H bond hydroxylation of halohydrocarbons is an appealing method for the synthesis of these compounds. Herein, P450DA mutants, which could improve or reverse the enantioselectivity, were generated by structure-guided directed evolution based on the X-ray crystal structure of P450DA-M3. It catalyzed the benzylic and allylic C–H bond hydroxylation of halohydrocarbons with regio-, chemo-, and enantioselectivity and provided the desirable enantiomers of both chiral γ-halohydrins (43–94% ee) and β-haloallyl alcohols (79–96% ee), while the halogen atoms and C═C bonds in the molecule remained unreacted. This enzymatic platform represents an example of catalytic systems achieving enantiodivergent control of C–H bond hydroxylation in halohydrocarbons via protein engineering.