On the reaction of (vinylimino)phosphoranes and related compounds. 20. Syntheses and properties of methanocyclodeca[b]pyridine ring systems

Nobuhiro Kanomata, Hiroyuki Kawaji, Makoto Nitta

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    Abstract

    Novel 2-[(triphenyl- and 2-[(tributylphosphoranylidene)amino]-1,6-methano[10]annulenes (8x,y) and 3-[(triphenyl- and 3-[(tributylphosphoranylidene)amino]-1,6-methano[10]annulenes (9x,y) were generated by the Staudinger reaction of 2- and 3-azido-1,6-methano[10]annulenes (5 and 6). The compound 8x was inert to α,β-unsaturated ketones, while compounds 8y and 9y were found to react with α,β-unsaturated ketones in enamine-alkylation process followed by aza-Wittig reaction and dehydrogenation to give 7,12- and 5,10-methanocyclodeca[b]pyridines 20a-f and 26a,f, respectively. The reactivity of 8 and 9 as well as the site selectivity of 9 was suggested by their 13C NMR spectra, in which the carbon signals of the nucleophilic center appear at higher field as compared to those of 1,6-methano[10]annulene. Structural properties of 20a-f and 26a,f were examined by 1H NMR and UV spectra. The 1H NMR spectra analyzing aromatic characters clarified both remarkable reduction of a ring current and appearance of bond alternation as compared to the parent 1,6-methano[10]annulene (1). The UV spectra exhibiting a prolonged cyclic conjugation are in contrast to their 10π electron analogues, 1,6-methano[10]annulene (1) and quinoline derivatives.

    Original languageEnglish
    Pages (from-to)618-625
    Number of pages8
    JournalJournal of Organic Chemistry
    Volume57
    Issue number2
    Publication statusPublished - 1992

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    ASJC Scopus subject areas

    • Organic Chemistry

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