A Computational Mechanistic Study of an Unprecedented Heck-Type Relay Reaction: Insight into the Origins of Regio- and Enantioselectivities.
Density functional theory (DFT) calculations (B3LYP and M06) have been utilized to study a newly reported Heck-type reaction that uses an allylic or alkenyl alcohol as substrate and palladium as catalyst in the form of a chelate with a chiral pyridine oxazoline (PyrOx) ligand. The reaction not only...
| Publicado en: | Journal of the American Chemical Society Vol. 136; no. 3; pp. 986 - 999 |
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| Autores principales: | , , , |
| Formato: | Artículo |
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American Chemical Society
1/22/2014
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| Acceso en línea: | Ver este registro en EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=hlh&AN=95065895&site=ehost-live header: @attributes: shortDbName: hlh uiTerm: 95065895 longDbName: Humanities International Complete uiTag: AN controlInfo: bkinfo: jinfo: jid: 00027863 ACS jtl: Journal of the American Chemical Society issn: 00027863 maglogo: N pubinfo: dt: 1/22/2014 vid: 136 iid: 3 pid: 997 pub: American Chemical Society artinfo: ui: 95065895 10.1021/ja410118m ppf: 986 ppct: 13 formats: tig: atl: A Computational Mechanistic Study of an Unprecedented Heck-Type Relay Reaction: Insight into the Origins of Regio- and Enantioselectivities. aug: au: Yanfeng Dang Shuanglin Qu Zhi-Xiang Wang Xiaotai Wang affil: School of Chemistry and Chemical Engineering, University of the Chinese Academy of Sciences, Beijing 100049, People's Republic of China Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, People's Republic of China Department of Chemistry, University of Colorado, Denver, Campus Box 194, P.O. Box 173364, Denver, Colorado 80217-3364, United States su: Computational mechanics Heck reaction Density functional theory Regioselectivity (Chemistry) Enantioselective catalysis Palladium catalysts Oxazoline synthesis Pyridine sug: subj: Computational mechanics Heck reaction Density functional theory Regioselectivity (Chemistry) Enantioselective catalysis Palladium catalysts Oxazoline synthesis Pyridine ab: Density functional theory (DFT) calculations (B3LYP and M06) have been utilized to study a newly reported Heck-type reaction that uses an allylic or alkenyl alcohol as substrate and palladium as catalyst in the form of a chelate with a chiral pyridine oxazoline (PyrOx) ligand. The reaction not only controls the regio- and enantioselectivities of arylation of the C=C bond, but also forms the carbonyl functionality up to four bonds away from the aryl substituent via tandem C=C bond migration and enol-to-keto conversion. Computations performed on representative reaction systems allow us to propose a detailed mechanism with several key steps. Initial oxidation of palladium(O) by aryldiazoniuni generates active arylpalladiuni(II) species that bind the C=C bond of an allylic or alkenyl alcohol. The activated C=C bond inserts into the palladium-aryl moiety to attain aryl substitution and a chiral carbon center, and the resulting complex undergoes β-hydride elimination to give a new C=C bond that can repeat the insertion! elimination process to move down the carbon chain to form an enol that tautornerizes to a highly stable carbonyl final product. The calculations reveal that the C=C bond migratory insertion step determines both the regioselectivity and the enantioselectivity of atylation, with the former arising mainly from the electronic effect of the hydroxyl group on the charge distribution over the C==C bond and the latter originating from a combination of steric repulsion, trans influence, and C-H/Π dispersion interactions. pubtype: Academic Journal doctype: Article src: R language: English refInfo: copyright: @attributes: flag: Y dt: @attributes: year: 2014 holdings: @attributes: islocal: N |
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