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.

利用双催化体系开发了一种有效且简便的方法，该方法可从相应的N-甲苯磺酰氮丙啶和CO ₂进行区域选择性合成N-甲苯磺恶唑烷酮类化合物，该体系包括早期过渡金属配位化合物（路易斯酸）和亲核助催化剂。在经筛选的路易斯酸中，当在碘化四丁基铵（TBAI）的存在下使用时，无卤素的五乙醇化铌（Nb（OEt）₅）表现出最佳的催化活性。由催化实验支持的系统DFT计算表明，CO _2的插入是该过程的速率决定步骤，并且高度依赖于铌中心的位阻。