title: Activation of aldehydes by exocyclic iridium(i)-η4:π2-diene complexes derived from 1,3-oxazolidin-2-ones.
abstract: The Ir(i) complexes [TpMe2Ir(η4-1,4-diene)] 2b and 2c react thermally with a variety of aromatic aldehydes, 3a-e, to generate the metallabicyclic compounds 4e-k and the Fischer-type carbenes 5a-b in moderate yields. These reactions are proposed to take place with the initial formation of η1-aldehyde adducts as key intermediates. The formation of the metallabicyclic compounds 4e-k involves a formal decarboxylation process at the exo-2-oxazolidinone diene and an ortho metallation of the aromatic ring. The generation of the Fischer-type carbenes 5a-b is the result of a series of metal-based rearranged intermediates with no decarboxylation observed. Treatment of the η4-diene complex 2b with a variety of Lewis bases induces a change in the binding mode of the diene ligand from η4:π2to η2:σ2to form the Ir(iii) derivatives 6b-d of composition TpMe2Ir-(η4:π2-1,4-diene)(L) (L = CO, MeCN, and C5H5N). A study of reactions of complex 2b with either mono- or poly-deuterated aldehydes was performed to understand the mechanisms of such processes. The results of these studies were used to determine plausible formation mechanisms of the metallabicyclic compounds 4e-4k and Fischer-type carbenes 5a-b compound series. These mechanisms were corroborated by density functional theory (DFT) calculations of the free energy profiles.
authors.affiliation: Área Académica de Química, Universidad Autónoma del Estado de Hidalgo, Carretera Pachuca-Tulancingo Km. 4.5, Mineral de la Reforma, Hidalgo 42090, México. salazar@uaeh.edu.mx.
authors.forename: Rosa
authors.initials: R
authors.lastname: Padilla
authors.forename: Verónica
authors.initials: V
authors.lastname: Salazar-Pereda
authors.forename: Daniel
authors.initials: D
authors.lastname: Mendoza-Espinosa
authors.forename: José M
authors.initials: JM
authors.lastname: Vásquez-Pérez
authors.forename: Noemí
authors.initials: N
authors.lastname: Andrade-López
authors.forename: Joaquín
authors.initials: J
authors.lastname: Tamariz
authors.forename: José G
authors.initials: JG
authors.lastname: Alvarado-Rodríguez
authors.forename: Julián
authors.initials: J
authors.lastname: Cruz-Borbolla