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Mechanisms of 1,4‐dipolar cycloaddition between propa‐1,2‐diene and imines catalyzed by PBu 3 : A DFT investigation
Author(s) -
Zhou DaGang
Publication year - 2020
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.4035
Subject(s) - chemistry , cycloaddition , catalysis , diene , electrophile , yield (engineering) , tributylphosphine , computational chemistry , medicinal chemistry , photochemistry , organic chemistry , natural rubber , materials science , metallurgy
The mechanisms for the 1,4‐dipolar catalytic cycloaddition between ethyl 2‐methylbuta‐2,3‐dienoate and ( E )‐N‐ethylidene‐4‐methylbenzenesulfonamide were studied with M06‐2X‐D3/6‐311+G(d,p) level, and IEFPCM was applied to simulate the solvent effect of DCM. The computational results suggested that ethyl 2‐methylbuta‐2,3‐dienoate and tributylphosphine first had an interaction; then, an electrophilic reaction occurred, and one new C─C bond has been formed; lastly, there are two possible processes to achieve this reaction. The Gibbs free energy surfaces indicate that the favor path is that PBu 3 as the catalyst and oxidant can help to accelerate this reaction to yield the final product ethyl 6‐methyl‐1‐tosyl‐1,2,5,6‐tetrahydropyridine‐3‐carboxylate with lower energy barrier. Our results demonstrated that these reactions can take place at a certain condition, in good agreement with the experimental observation.