Enzyme-Mediated Transformation of Epoxides to Oxazolidinones

Significance

An enzyme-mediated enantioselective ring opening-cyclization sequence of epoxides to oxazolidinones is reported. The used biocatalyst was the bacterial halohydrin dehalogenase enzyme from Agrobacterium radiobacter. Cyanate is used as nucleophile in the ring opening to an intermediary isocyanate-cyanate species. As cyanate is an ambident nucleophile, an isocyanate and a cyanate adduct can be formed under enzyme influence. However, the cyanates are assumed to be unstable and isomerize to the isocyanates quickly. These intermediates then undergo rapid cyclization. The size of the epoxide substituents is assumed to dictate the selectivity of the reaction.