Synthesis of new 3,5-diarylisoxazolidines by cycloaddition of oxaziridines and alkenes

[3+2] Cycloaddition reaction between aliphatic alkynes and oxaziridines

“…7,8,9,10 Moreover, it has been reported that oxaziridines undergo a cycloaddition reaction with a variety of heterocumulenes to afford a different set of five-membered heterocycles. 7,8,9,10,11 We have recently described a simple and highly efficient [3+2] cycloaddition reaction between a variety of aryl alkenes 12 or alkynes 13 and 2-alkyl-3-aryloxaziridines. This new behaviour led to 2-alkyl-3,5-diarylisoxazolidines and 2-alkyl-3,5-diarylisoxazolines, respectively, as shown in Scheme 1.…”

Synthesis of Dihydrobenzisoxazoles by the [3 + 2] Cycloaddition of Arynes and Oxaziridines

“…In the first possible mechanism (Path A), insertion of the aryne into the C-O bond of the oxaziridine ring occurs by a concerted mechanism. Agawa28 and Troisi4 have suggested a similar cycloaddition mechanism for the formation of diarylisoxazolidine derivatives from oxaziridines. Another possible mechanism involves initial formation of a nitrone at the higher temperatures employed.…”

“…Troisi et al . have also compared the one-step mechanism to the nitrone mechanism in similar cyclization reactions 3,4. They suggest that Path A is more probable than the nitrone mechanism.…”

2-tert-Butyl-3-phenyloxaziridine

“…This reaction is applicable for synthesis of glucosylaminoheterocycles. 13 2-tert-Butyl-3phenyloxaziridine (and similar) underwent cycloaddition with a variety of aryl alkenes to afford stable 3,5-diarylisoxazolidines (cis > trans). The steric hindrance of the tert-butyl group on the nitrogen atom of the oxaziridines is responsible for the stereoselectivity of the cycloaddition (eq 4).…”