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Protonation of captodative trifluoromethylated aminoalkenes and isomerization of their salts. An ab initio study
Author(s) -
Kondrashov E. V.,
Chipani. N.,
Aksamentova T. N.,
Rulev A. Yu.
Publication year - 2012
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.1897
Subject(s) - chemistry , protonation , intramolecular force , isomerization , intermolecular force , iminium , ab initio , enamine , regioselectivity , computational chemistry , ab initio quantum chemistry methods , morpholine , molecular orbital , photochemistry , medicinal chemistry , stereochemistry , molecule , organic chemistry , ion , catalysis
A study of the regioselectivity of protonation of captodative trifluoromethylated enamines was carried out using MP2/6‐311 + G(d,p) calculations and the natural bond orbital analysis. The central issue of this research concerns the influence of the electron‐withdrawing group, which is not capable of the π,π ‐conjugation, on the properties of captodative enamines and their salts. The presence of CF 3 group in such type of enamines levels the energy of their N‐protonated and C‐protonated forms. The transition states were found for both intramolecular and intermolecular processes of the proton transfer. The more possible mechanism of the isomerization of enammonium and iminium cations includes the proton transfer from N‐protonated form to olefinic carbon atom of the starting enamine. The transition state energies, which correspond to intermolecular process, are relatively low (11–13 kcal mol –1 ) in contrast to the intramolecular pathway (64–69 kcal mol –1 ). Copyright © 2011 John Wiley & Sons, Ltd.