Mechanistic Study of the Manganese-Catalyzed [2 + 2 + 2] Annulation of 1,3-Dicarbonyl Compounds and Terminal Alkynes.
The manganese-catalyzed dehydrative [2 + 2 + 2] annulation reaction of a 1 ,3-dicarbonyl compound and a terminal alkyne provides an efficient and regioselective synthesis of a substituted benzerie derivative, highlighted by the exclusive formation of a p-terphenyl derivative from an aryl acetylene....
| Publicado en: | Journal of the American Chemical Society Vol. 131; no. 11; pp. 4099 - 4110 |
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| Autores principales: | , , , , |
| Formato: | Artículo |
| Publicado: |
American Chemical Society
3/25/2009
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| Materias: | |
| 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=37258144&site=ehost-live header: @attributes: shortDbName: hlh uiTerm: 37258144 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: 3/25/2009 vid: 131 iid: 11 pid: 997 pub: American Chemical Society artinfo: ui: 37258144 10.1021/ja809202y ppf: 4099 ppct: 11 formats: tig: atl: Mechanistic Study of the Manganese-Catalyzed [2 + 2 + 2] Annulation of 1,3-Dicarbonyl Compounds and Terminal Alkynes. aug: au: Yoshikai, Naohiko Zhang, Song-Lin Yamagata, Ken-ichi Tsuji, Hayato Nakamura, Eiichi affil: Department of Chemistry, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan Department of Chemistry, University of Science and Technology of China, Hefei 230026, China su: Manganese Alkynes Stereochemistry Density functionals Carbonyl compounds Catalysis sug: subj: Manganese Alkynes Stereochemistry Density functionals Carbonyl compounds Catalysis ab: The manganese-catalyzed dehydrative [2 + 2 + 2] annulation reaction of a 1 ,3-dicarbonyl compound and a terminal alkyne provides an efficient and regioselective synthesis of a substituted benzerie derivative, highlighted by the exclusive formation of a p-terphenyl derivative from an aryl acetylene. The mechanism and the origin of the regioselectivity of the reaction were explored by experiments and density functional theory (DFT) calculations. Experimental data revealed the cis stereochemistry of a cyclohexadienol precursor to the benzene product and suggested that two reaction pathways may operate competitively - sequential carbometalation reactions of a manganese enolate and formation of a manganacyclopentadiene intermediate. The DFT study supported the first possibility, namely that the reaction involves three steps: (1) addition of a manganese enolate of a 1,3-dicarbonyl compound to a terminal alkyne to give a vinylmanganese complex, (2) insertion of a second alkyne into the vinyl-Mn bond to give a dienylmanganese complex, and (3) intramolecular nucleophilic addition of the dienylmanganese to the carbonyl group. This mechanism is consistent with the experimental facts such as the perfect regioselectivity of the reaction of an aryl acetylene, the moderate regioselectivity of the reaction of an alkyl acetylene, and the stereochemistry of the annulation product. An alternative mechanism involving a manganacyclopentadiene intermediate failed to account for the experimental regioselectivity, although it may be occurring as a very minor competitive pathway. pubtype: Academic Journal doctype: Article src: R language: English refInfo: copyright: @attributes: flag: Y dt: @attributes: year: 2009 holdings: @attributes: islocal: N |
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