Tuning the strain effect to induce selectivity through intramolecular nitrene insertion into an adjacent methoxy C[sbnd]H bond leading to form a new benzoxazole: experimental and computational studies

Abstract

Pyrolysis of azido-meta-meconine yields only a single product 1D, which has been characterized spectroscopically (1H NMR, 13C NMR, HSQC, DEPT & MS). These results reveal that the fused five-member lactone ring can influence the product selectivity. The DFT calculations suggest the formation of favourable oxazolidine intermediate compared to azirine (1Z) and ketenimine (1H) intermediates. The isodesmic analysis showed that the fused lactone aryl nitrene (1N) would have more strain to form azirine (1Z) intermediate than the corresponding aryl nitrene (1M).