Synthesis of bicyclo[4.1.0]heptenes via palladium-catalyzed intramolecular coupling-cyclization of 3-(cyclohexa-2,4-dienyl)pentane-2,4-dione with β-styryl bromides

Ming-Chang P. Yeh, Wen Cheng Tsao, Yen Jung Wang, Hui Fen Pai

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Palladium-catalyzed intramolecular coupling-cyclization of 3-(cyclohexa-2,4-dienyl)pentane-2,4-dione with β-styryl bromides proceeds in regio- and stereoselective fashions to give 2-styryl-substituted bicyclo[4.1.0]hept-3-enes in good yields. The formation of the bicyclo[4.1.0]hept-3-enes was rationalized by starting with oxidative addition of Pd(PPh3)4 to the carbon-bromine bond of β-styryl bromide (RBr) to give Pd(R)BrLn. Reaction of Pd(R)BrLn with Ag 2CO3 generates a cationic RPd(II)Ln species. Chelation of the RPd(II)Ln cation to both the O-enolate of the ketone and the proximal double bond followed by attack of the enolate on the activated double bond gave a bicyclic η1-allylpalladium intermediate. The postulated bicyclic η1-allylpalladium intermediate leads to 2-styryl-substituted bicyclo[4.1.0]hept-3-enes with exclusive regio- and stereoselectivities after reductive elimination.

Original languageEnglish
Pages (from-to)4271-4277
Number of pages7
JournalOrganometallics
Volume26
Issue number17
DOIs
Publication statusPublished - 2007 Aug 13

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pentanes
Cyclization
Palladium
Dione
Bromides
palladium
bromides
Stereoselectivity
Bromine
Regioselectivity
chelation
synthesis
bromine
Chelation
Ketones
ketones
attack
Cations
elimination
Carbon

ASJC Scopus subject areas

  • Inorganic Chemistry
  • Organic Chemistry

Cite this

Synthesis of bicyclo[4.1.0]heptenes via palladium-catalyzed intramolecular coupling-cyclization of 3-(cyclohexa-2,4-dienyl)pentane-2,4-dione with β-styryl bromides. / Yeh, Ming-Chang P.; Tsao, Wen Cheng; Wang, Yen Jung; Pai, Hui Fen.

In: Organometallics, Vol. 26, No. 17, 13.08.2007, p. 4271-4277.

Research output: Contribution to journalArticle

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