Diels–Alder and ene reactions of singlet oxygen, nitroso compounds and triazolinediones: transition states and mechanisms from contemporary theory

• DOI: 10.1039/b111251c
• Publication Date: 2002-07-26T09:25:24Z
• Authors: Andrew G. Leach; K. N. Houk
• Keywords: Ene reaction; Nitroso Compounds; HOMO/LUMO; Transition state; Antibonding molecular orbital

Singlet oxygen, nitroso compounds and triazolinediones have similar electronic structures: they share a low lying LUMO, making them powerful electrophiles, high HOMO, orthogonal to the LUMO consisting of an antibonding combination lone paris. This bestows some nucleophilic character on these species. We describe number studies employing best levels theory currently available for systems this size demonstrate that Diels-Alder ene reactions three species are calculated show subtle changes in mechanism. The calculations been calibrated, wherever possible, by comparison experimental observations including measured activation reaction energies, regio- stereo-selectivities, intermediates observed either spectroscopically or trapping, kinetic isotope effects.