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Indexed by:期刊论文

Date of Publication:2005-06-24

Journal:JOURNAL OF ORGANIC CHEMISTRY

Included Journals:SCIE、EI、Scopus

Volume:70

Issue:13

Page Number:4910-4917

ISSN No.:0022-3263

Abstract:The Diels-Alder (DA) reactions of various substituted ethenes (methyl vinyl ether (MVE), styrene, and methyl vinyl ketone (MVK)) with o-quinone methides (o-QM) are studied by means of density functional theory (DFT) at the B3LYP/6-31G(d,p) level. On the basis of analysis for frontier molecular orbital and comparison of the activation energies for different reaction pathways, the ortho attack modes present transition structures more stable than the meta ones. The reactivity, ortho selectivity, and asynchronicity are enhanced with the increase of the electron-releasing character of the substitute on ethene fragment. The discussions for the charge distribution and charge transfer on different transition states indicate that there are different molecular mechanisms for the different substituted ethenes. The calculations show that the effect of solvent decreases the activation energy and increases the asynchronicity. The results also indicate that the hydrogen-bond formation between chloroform and the carbonyl oxygen of the o-QM lowers the activation energies and increases the asynchronicity.