Nitrone cycloaddition : peracid oxidation of perhydro-1,2-oxazolo[3,2-c][1,4]oxazines
作者:Sk.Asrof Ali、Hasan A. Al-Muallem
DOI:10.1016/s0040-4020(01)87213-6
日期:1993.8
2-oxazolo[3,2-c][1,4]oxazines (2) and (6) in aprotic solvent is dictated by orientation of lone pair of electrons on nitrogen. In contrast to the case with the corresponding hexahydro-2H-isoxazolo[2,3-a]pyridines (17), the oxidation of (2) gives mainly an equilibrium mixture of aldonitrone (3) and its hydroxylamine tautomer (4) which undergo stereoselectivecycloaddition with styrene and methyl methacrylate
Peracid induced ring opening of isoxazolidines. A mechanistic study.
作者:Sk.Asrof Ali、Mohammed I.M. Wazeer
DOI:10.1016/s0040-4039(00)79856-x
日期:1992.5
Conformational analysis and mechanistic study of peracid induced ring opening of several isoxazolidines have been carried out. The orientation of the nitrogen lone pair dictates the regiochemistry of the ring opening which involves an intramolecular kinetic deprotonation of a nitroxonium ion intermediate.