A DFT study of Diels-Alder reactions of o-quinone methides and various substituted ethenes: selectivity and reaction mechanism.

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