121990-12-3Relevant academic research and scientific papers
CYCLIZATION WITH NITRENIUM IONS GENERATED FROM N-METHOXY- OR N-ALLYLOXY-N-CHLOROAMIDES WITH ANHYDROUS ZINC ACETATE. SYNTHESIS OF N-HYDROXY- AND N-METHOXYNITROGEN HETEROCYCLIC COMPOUNDS
Kikugawa, Yasuo,Shimada, Masahiro,Matsumoto, Kazuhiro
, p. 293 - 302 (2007/10/02)
Electrophilic intramolecular aromatic substitution with an N-methoxy- or an N-allyloxyacylnitrenium ion, generated by treatment of an N-methoxy- or an N-allyloxy-N-chloroamide with anhydrous zinc acetate in nitromethane, leads to formation of a nitrogen h
Electrophilic Aromatic Substitution with N-Methoxy-N-acylnitrenium Ions Generated from N-Chloro-N-methoxyamides: Syntheses of Nitrogen Heterocyclic Compounds Bearing a N-Methoxyamide Group
Kawase, Masami,Kitamura, Takahiro,Kikugawa, Yasuo
, p. 3394 - 3403 (2007/10/02)
N-Methoxy-N-acylnitrenium ions (II), generated by treatment of N-chloro-N-methoxyamides with silver carbonate in trifluoroacetic acid, react with arenes to give N-aryl-N-methoxyamides in good yields.In the case of the intramolecular cyclization of N-chloro-N-methoxy-2-phenylacetamides, the mode of cyclization is highly dependent on the nature of ortho or para substituent groups.Nitrenium ions II can primarily attack three positions (C-1, C-2, and C-6) of a phenyl ring.Normally II attack C-6.On the other hand, when the ortho position was occupied with a substituent group, II attacked both C-2 and C-6, in the former case followed by a 1,2-substituent migration, which was proved by a deuterium labeling experiment.Especially, when a methoxy group is substituted on ortho or para position, II attack C-1 due to the effect of the electron-releasing methoxy group to give spiro dienone compounds 39.A general discussion of the utility and mechanistic details of these reactions is presented.
