title: The final steps of the Oppolzer cyclization: mechanism of the insertion of alkenes into allylpalladium(II) complexes.
abstract: We report here the results of a computational study on the the mechanism of the Oppolzer cyclization. These results lead us to conclude that the insertion of olefins in Pd-allyl complexes probably takes place directly from the eta(3)-allyl species. The presence of a phosphane ligand in the reagents plays the role of enhancing the electron density on the Pd atom; this makes the alkene moiety more reactive towards insertion by back-donation from the metal. The results also indicate that the configuration of the new stereogenic centers is fixed in the insertion of the alkene into the (eta(3)-allyl)palladium species.
authors.affiliation: Departamento de Química Orgánica, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain.
authors.forename: Diego J
authors.initials: DJ
authors.lastname: Cárdenas
authors.forename: Manuel
authors.initials: M
authors.lastname: Alcamí
authors.forename: Fernando
authors.initials: F
authors.lastname: Cossío
authors.forename: María
authors.initials: M
authors.lastname: Méndez
authors.forename: Antonio M
authors.initials: AM
authors.lastname: Echavarren