Open AccessEffect of the anionic center hydration on the activation barrier of intramolecular nucleophilic addition in αβ-unsaturated oximes
Author(s) -
A. G. Pradedova,
В. Б. Кобычев
Publication year - 2021
Publication title -
journal of physics. conference series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 85
eISSN - 1742-6596
pISSN - 1742-6588
DOI - 10.1088/1742-6596/1847/1/012057
Subject(s) - chemistry , intramolecular force , nucleophile , hydroxide , nucleophilic addition , molecule , solvation , oxime , imine , activation barrier , medicinal chemistry , stereochemistry , catalysis , organic chemistry
The mechanism of intramolecular nucleophilic addition in αβ-unsaturated oximes, as well as the effect of the anionic center hydration with one and two water molecules on the activation barriers of intramolecular cyclization, was studied using the B2PLYP-D2/6-311+G**//B3LYP(D)/6-31+G* method with the solvation effects included within the SMD model. The activation barrier for nucleophilic addition of the anionic center of the oxime group to the carbon skeleton of 3-ethyl-N-hydroxy-5-phenylpenten-3-imine-2 is about 21 kcal/mol. During the hydration of the anionic center with one water molecule, a strong complex is formed, which increases the activation barrier by ∼ 6 kcal / mol. The addition of a second water molecule leads to an even higher activation barrier ( ΔG ‡ = 28 kcal/mol), but promotes the binding of the leaving hydroxide ion.