title: On the 1,3-dipolar cycloaddition reactions of indenone with N-N-C dipoles: density functional theory calculations.
abstract: Density functional theory (DFT) calculations at the B3LYP/6-311G* theoretical level have been performed to study the 1,3-dipolar cycloaddition (1,3-DC) reactions between indenone (1) and different 1,3-dipoles (diazomethane and N-methyl C-methoxy carbonyl nitrilimine, compounds 2 and 3, respectively). The geometrical and energetic properties were analysed for the different reactives, transition states and cycloadducts formed (compounds 4-11). The reactions proceed in the gas-phase by an asynchronous concerted mechanism, yielding different regiochemistry dependent on the 1,3-dipole chosen, although with dipole 3 some degree of synchrony was found in the formation of cycloadduct 5. The 1,3-DC between 1 and 3 was regioselective, being the cycloadduct 11 favoured against 9. The NMR chemical shift parameters (GIAO method) were also calculated for the reactives and cycloadducts.
authors.affiliation: Departamento de Química Orgánica, Grupo de Modelización y Diseño Molecular, Campus Fuentenueva, Universidad de Granada, 18071 Granada, Spain. ajalbout@ejmaps.org
authors.forename: Abraham F
authors.initials: AF
authors.lastname: Jalbout
authors.forename: Z
authors.initials: Z
authors.lastname: Jiang
authors.forename: H
authors.initials: H
authors.lastname: Abou-Rachid
authors.forename: N
authors.initials: N
authors.lastname: Najat Benkaddour
mesh_terms: D002623:Chemistry Techniques, Analytical / Q000379:methods*; D003978:Diazomethane / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy
chemical_list: D003978:Diazomethane