Investigations on regio??and stereoselectivities in cycloadditions involving α??(3??pyridyl)??N??phenylnitrone: Development of an efficient route to novel nicotine analogs

G Singh, MPS Ishar, NK Girdhar…

Index: Singh, Gurpinder; Ishar; Girdhar, Navdeep K.; Singh, Lakhwinder Journal of Heterocyclic Chemistry, 2005 , vol. 42, # 6 p. 1047 - 1054

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Citation Number: 8

Abstract

Abstract Thermal reactions of hitherto α-(3-pyridyl)-N-phenylnitrone (1) with mono- substituted electron-rich and electron-neutral dipolarophiles are regio-, and stereo-selective (exo-selective), controlled by LUMO-dipole-HOMO-dipolarophile interaction, and furnish syn- 5-substituted-3-(3-pyridyl)-isoxazolidines (5) in high yields. With electron deficient dipolarophiles such as acrylonitrile there is observed a loss of regioselectivity as well as ...