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 language | English |
|---|---|
| Pages (from-to) | 4271-4277 |
| Number of pages | 7 |
| Journal | Organometallics |
| Volume | 26 |
| Issue number | 17 |
| DOIs | |
| Publication status | Published - 2007 Aug 13 |
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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 journal › Article
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TY - JOUR
T1 - 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
AU - Yeh, Ming Chang P
AU - Tsao, Wen Cheng
AU - Wang, Yen Jung
AU - Pai, Hui Fen
PY - 2007/8/13
Y1 - 2007/8/13
N2 - 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.
AB - 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.
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U2 - 10.1021/om7004386
DO - 10.1021/om7004386
M3 - Article
AN - SCOPUS:34548181089
VL - 26
SP - 4271
EP - 4277
JO - Organometallics
JF - Organometallics
SN - 0276-7333
IS - 17
ER -