CAN-Promoted Boc2O-Mediated Cascade Conversion of Aziridines to Oxazolidinones

Abstract An efficient CAN-promoted Boc2O-mediated cascade conversion of aziridines to oxazolidinones has been developed. The transformation proceeds under mild, CO2-free conditions and provides structurally diverse oxazolidinones in 16–99% yields (46 examples), with gram-scale reactions demonstrating its synthetic practicality. Boc2O serves as an alternative carbonyl source and is proposed to generate a reactive tert-butyl carbonate species that undergoes nucleophilic aziridine ring opening followed by intramolecular cyclization. Control experiments identify CAN as the most effective promoter examined and demonstrate that DBU and TBAB cooperatively enhance reaction efficiency. Stereochemical studies are consistent with an SN2-type ring-opening pathway. This methodology provides a practical complement to existing CO2-based approaches and expands the synthetic utility of Boc2O-mediated cascade chemistry.