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Theoretical prediction on the synthesis of 2,3‐dihydropyridines through Co(III)‐catalysed reaction of unsaturated oximes with alkenes
Author(s) -
Zhang XiangBiao,
Yu BinBin,
Si ShengMeng,
Wang Song
Publication year - 2017
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.25353
Subject(s) - chemistry , substituent , exergonic reaction , catalysis , medicinal chemistry , reductive elimination , oxime , catalytic cycle , deprotonation , organic chemistry , ion
Cobalt‐based catalysts can replace the homologous group‐9 rhodium‐based ones. Herein, we used density functional theory (DFT) calculations to predict the synthesis of 2,3‐dihydropyridines using α,β‐unsaturated oxime pivalates and alkenes catalysed by [Cp*CoOAc] + instead of [Cp*RhOAc] + . The catalytic cycle involves reversible acetate‐assisted metalation‐deprotonation, migratory insertion of alkenes, and reductive elimination/N‐O cleavage. The migratory insertion of alkenes was determined to be the rate‐determining step, and the reaction is irreversible due to the strongly exergonic reductive elimination/NO cleavage. When using the CF 3 ‐substituted Cp*Co(III) catalyst, the apparent activation energy indicates that the title reaction can proceed at higher temperatures. Electron‐withdrawing substituent groups on Cp* facilitate the reaction. In contrast, substituting phenyl with the electron‐deficient p‐CF 3 ‐phenyl at the 2‐position of α,β‐unsaturated oxime pivalate hinders the reaction, and so does the use of polarized alkenes with electron‐withdrawing substituent groups