Biocatalytic Regio- and Enantiocomplementary Synthesis of Chiral Aryloxazolidinones

We described the protein engineering of the halohydrin dehalogenase HheG to enhance its R enantioselectivity for the synthesis of chiral 4-aryloxazolidinones via alpha-regioselective ring-opening of aryl epoxides with cyanate. Additionally, we achieved the inversion of its regioselectivity and enantioselectivity, resulting in a HheG variant tailored for the synthesis of chiral 5-aryloxazolidinones via beta-regioselective and S-enantioselective ring-opening of aryl epoxides with cyanate. Leveraging these engineered mutants, we developed a biocatalytic platform capable of synthesis of both chiral 4-aryloxazolidinones (up to 47% yield, 98% ee, and 99% regioselectivity) and chiral 5-aryloxazolidinones (up to 46% yield, >99% ee, and 98% regioselectivity). Furthermore, a collaborative approach utilizing two regio- and enantioselective HheG mutants has been demonstrated to enable the simultaneous synthesis of chiral 4-aryloxazolidinones and chiral 5-aryloxazolidinones.