Mechanism and proton activating factors in base-induced beta-elimination reactions of N[2-(4-pyridyl)ethyl]quinuclidinium and N-[2-(2-pyridyl)ethyl]quinuclidinium salts
S. Alunni et al., Mechanism and proton activating factors in base-induced beta-elimination reactions of N[2-(4-pyridyl)ethyl]quinuclidinium and N-[2-(2-pyridyl)ethyl]quinuclidinium salts, J CHEM S P2, (3), 2000, pp. 453-457
Citations number
16
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 2
beta-Elimination reactions of N-[2-(4-pyridyl)ethyl]quinuclidinium and N-[2
-(2-pyridyl)ethyl]quinuclidinium salts (N) in acetohydroxamate-acetohydroxa
mic acid buffer, H2O, mu = 1 M KCl, 50 degrees C, with the formation of 4-
or 2-vinylpyridine, respectively, proceed by an E1cb mechanism with carbon
deprotonation occurring in the substrates protonated at the pyridine ring (
NH+). The formation of the intermediate carbanion has a high degree of reve
rsibility. The systems consistently present H/D exchange. NH+ is much more
reactive than N; this can be attributed to the strong stabilization of the
intermediate carbanion formed from NH+ due to resonance.