title: Palladium-catalyzed intramolecular oxidative alkylation of 4-pentenyl beta-dicarbonyl compounds.
abstract: Reaction of 8-nonene-2,4-dione with a catalytic amount of [PdCl2(CH3CN)2] (2; 5 mol %) and a stoichiometric amount of CuCl2 (2.5 equiv) at room temperature for 3 h led to oxidative alkylation and formation of 2-acetyl-3-methyl-2-cyclohexenone in 80 % isolated yield. The oxidative alkylation of 4-pentenyl beta-diketones tolerated a number of terminal acyl groups and substitution at the C1 and C3 carbon atoms of the 4-pentenyl chain. Likewise, 4-pentenyl beta-keto esters that possessed geminal disubstitution at the C1, C2, or C3 carbon atom of the 4-pentenyl chain cyclized to form 2-carboalkoxy-2-cyclohexenones in moderate to good yield as the exclusive cyclized product. Deuterium-labeling experiments provided information regarding the mechanism of the palladium-catalyzed oxidative alkylation of 4-pentenyl beta-dicarbonyl compounds.
authors.affiliation: P. M. Gross Chemical Laboratory, Duke University, Durham, North Carolina 27708-0346, USA.
authors.forename: Cong
authors.initials: C
authors.lastname: Liu
authors.forename: Xiang
authors.initials: X
authors.lastname: Wang
authors.forename: Tao
authors.initials: T
authors.lastname: Pei
authors.forename: Ross A
authors.initials: RA
authors.lastname: Widenhoefer