An efficient and facile approach to the regioselective synthesis of N-tosyloxazolidinones from the corresponding N-tosylaziridines and CO2 was developed using dual catalytic systems involving an early transition metal coordination compound as a Lewis acid and a nucleophilic cocatalyst. Among the screened Lewis acids, halogen-free niobium pentaethoxide (Nb(OEt)5) displayed the best catalytic activity when used in the presence of tetrabutylammonium iodide (TBAI). Systematic DFT calculations, supported by catalytic experiments, demonstrate that CO2 insertion is the rate determining step for this process and it is highly dependent on the steric hindrance at the niobium center.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: A.P. thanks the Spanish MINECO for a project CTQ2014-59832-JIN, and EU for a FEDER fund (UNGI08-4E-003). V.D.E. thanks the Thailand Research Fund (Grant No. RSA6080059) for funding this research. S.A. acknowledges financial support through postdoctoral fellowship from the Vidyasirimedhi Institute of Science and Technology.