Computational Results Provide a Synthetically Unprecedented Explanation for the beta-Regioselectivity in the Rh-catalyzed Hydroformylation of Vinylidenic Substrates (Articolo in rivista)

Type

• Articolo in rivista (Classe)
• Prodotto della ricerca (Classe)

Label

• Computational Results Provide a Synthetically Unprecedented Explanation for the beta-Regioselectivity in the Rh-catalyzed Hydroformylation of Vinylidenic Substrates (Articolo in rivista) (literal)

Anno

• 2009-01-01T00:00:00+01:00 (literal)

Alternative label

• Ghio C., Lazzaroni R., Alagona* G. (2009)
  Computational Results Provide a Synthetically Unprecedented Explanation for the beta-Regioselectivity in the Rh-catalyzed Hydroformylation of Vinylidenic Substrates
  in European journal of inorganic chemistry (Print)
  (literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori

• Ghio C., Lazzaroni R., Alagona* G. (literal)

Pagina inizio

• 98 (literal)

Pagina fine

• 103 (literal)

Rivista

• European journal of inorganic chemistry (Rivista)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#note

• DOI: 10.1002/ejic.200800684 - Published online: Nov. 28, 2008 - Supporting information for this article is available on the WWW under http://www.eurjic.org (literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#descrizioneSinteticaDelProdotto

• Theoretical calculations on the hydroformylation of 1,1-diphenylethene, carried out on the approaching path of the fourth CO group, demonstrate that there is an unexpected and remarkably high free energy activation barrier for the tertiary alkyl-Rh(CO)3 intermediate, whereas the reaction pathway is practically downhill for the linear one, once the linear alkyl-Rh(CO)3…CO adduct has been formed. For the present substrate, this barrier can be ascribed to the agostic interaction with the pi- density of one of the aromatic rings. The formation of the alkyl-Rh(CO)4 species, overlooked thus far because of its thermodynamic stability, instead of the subsequent steps, i.e. the insertion of an alkyl group onto the coordinated CO group, previously hypothesised in the literature, as well as the H2 oxidative addition and reductive elimination, whether reachable, is actually responsible for the absence of the quaternary aldehyde. This is a novel finding. Nonetheless, the barrier for the CO addition to the branched intermediate is not a peculiarity of this system: other substrates show a similar behaviour. (literal)

Note

• ISI Web of Science (WOS) (literal)

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• G.C.: IPCF-CNR, MML, Pisa; L.R.: DCCI, Università di Pisa, Pisa; A.G.: IPCF-CNR, MML, Pisa (literal)

Titolo

• Computational Results Provide a Synthetically Unprecedented Explanation for the beta-Regioselectivity in the Rh-catalyzed Hydroformylation of Vinylidenic Substrates (literal)

Abstract

• The approaching path of CO to the alkyl-Rh(CO)3 intermediate, considered for 1,1-diphenylethene as a test case to investigate the reason of its failure to produce quaternary aldehydes in hydroformylation reactions, shows a remarkable activation barrier in DFT calculations for the branched alkyl-Rh intermediate, but not for the linear one. Consideration of the free energy associated to this step strengthens this result, whereas the other steps remain fairly comparable. The path leading to the branched aldehyde is thus abandoned early, and this species then returns to the catalyst and the olefin, with subsequent reformation of the branched and linear alkyl-Rh intermediates until consumption of the olefin. The branched backward pathway is more favourable indeed than the forward one, as can be inferred from its free energy reaction profile. The heuristic value of theoretical/computational methods in exploring experimentally inaccessible species and in rationalizing the results, together with the importance of the organic part structure in organometallic complexes, is also put forward. (literal)

Prodotto di

• Istituto per i processi chimico-fisici (IPCF) (Istituto)
• Meccanismi di reazione in vacuo, in soluzione, nel campo di enzimi e meccanismi dell'adsorbimento di molecole su superfici (PM.P07.007.002) (Modulo)
• Modellizzazione di proprietà e reattività di molecole biologiche e biomimetiche (MD.P01.013.001) (Modulo)

Autore CNR

• GIULIANO ALAGONA (Unità di personale interno)
• CATERINA ENRICA GHIO (Persona)

Insieme di parole chiave

• Parole chiave di "Computational Results Provide a Synthetically Unprecedented Explanation for the beta-Regioselectivity in the Rh-catalyzed Hydroformylation of Vinylidenic Substrates" (Insieme di parole chiave)

Incoming links:

Prodotto

• Istituto per i processi chimico-fisici (IPCF) (Istituto)
• Modellizzazione di proprietà e reattività di molecole biologiche e biomimetiche (MD.P01.013.001) (Modulo)
• Meccanismi di reazione in vacuo, in soluzione, nel campo di enzimi e meccanismi dell'adsorbimento di molecole su superfici (PM.P07.007.002) (Modulo)

Autore CNR di

• CATERINA ENRICA GHIO (Persona)
• GIULIANO ALAGONA (Unità di personale interno)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#rivistaDi

• European journal of inorganic chemistry (Rivista)

Insieme di parole chiave di

• Parole chiave di "Computational Results Provide a Synthetically Unprecedented Explanation for the beta-Regioselectivity in the Rh-catalyzed Hydroformylation of Vinylidenic Substrates" (Insieme di parole chiave)