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A DFT Study on the Mechanism of the Cycloaddition Reaction of CO 2 to Epoxides Catalyzed by Zn(Salphen) Complexes
Author(s) -
CastroGómez Fernando,
Salassa Giovanni,
Kleij Arjan W.,
Bo Carles
Publication year - 2013
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201203985
Subject(s) - cycloaddition , catalysis , chemistry , ring (chemistry) , reaction mechanism , methylene , epoxide , carbonate , medicinal chemistry , stereochemistry , polymer chemistry , organic chemistry
The reaction mechanism for the Zn(salphen)/NBu 4 X (X=Br, I) mediated cycloaddition of CO 2 to a series of epoxides, affording five‐membered cyclic carbonate products has been investigated in detail by using DFT methods. The ring‐opening step of the process was examined and the preference for opening at the methylene (C β ) or methine carbon (C α ) was established. Furthermore, calculations were performed to clarify the reasons for the lethargic behavior of internal epoxides in the presence of the binary catalyst. Also, the CO 2 insertion and the ring‐closing steps have been explored for six differently substituted epoxides and proved to be significantly more challenging compared with the ring‐opening step. The computational findings should allow the design and application of more efficient catalysts for organic carbonate formation.