Palladium-catalyzed cyclization of alkenyl β-keto esters in the presence of chlorotrimethylsilaneElectronic supplementary information (ESI) available: experimental procedures, analytical and spectroscopic data for new compounds and cyclohexanones. See http://www.rsc.org/suppdata/cc/b1/b111644d/

2002 ◽  
pp. 650-651 ◽  
Author(s):  
Tao Pei ◽  
Ross A. Widenhoefer
Keyword(s):  
Spectroscopic Data ◽  
Supplementary Information ◽  
Keto Esters ◽  
Palladium Catalyzed ◽  
New Compounds

Synthese und Kristallstrukturen einiger Tetramethylstibonium-Hydrogendicarboxylate / Synthesis and Crystal Structures of Some Tetramethylstibonium Hydrogendicarboxylates

1982 ◽  
Vol 37 (11) ◽  
pp. 1393-1401 ◽  
Author(s):  
Beatrix Milewski-Mahrla ◽  
Hubert Schmidbaur
Keyword(s):  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Spectroscopic Data ◽  
Molar Ratio ◽  
Ionic Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Carboxylate Oxygen ◽  
Donor Acceptor ◽  
New Compounds

Reactions of pentamethylantimony (CH3)5Sb with carboxylic acids in the molar ratio 1:2 afford one equivalent of methane and essentially quantitative yields of crystalline tetramothylstibonium hydrogendicarboxylates. Six new compounds of this series have been synthesized using benzoic, o-phthalic, salicylic, 4-ethoxy-salicylic, oxalic, and malic acid, and characterized by analytical and spectroscopic data. An ionic structure with strong hydrogen bonds in the anionic components is proposed.The crystal structures of the hydrogen-dibenzoato (1), hydrogen-ortho-plithalato (2) and 4-ethoxy-hydrogen-salicylate (3) were determined by single crystal X-ray diffraction. The compounds can be described as having ionic lattices with some donor-acceptor inter­actions between the stibonium centers and the carboxylate oxygen atoms. The anions are characterized by strong hydrogen bonds O...H...O. Thus, the (CH3)4Sb-tetrahedron in 1 is distorted by two benzoate oxygon atoms (at 304(2) and 340(2) pin). The cation in 2 is largely undistorted and the anion has a hydrogenphthalate hydrogen bond of d(O...H...O) = 232 pm. The cation-anion contact in 3 is as short as d(Sb-O) = 289 pm rendering the Sb atom pentacoordinate.

scholarly journals Palladium-catalyzed alkylation of unactivated olefins

2004 ◽  
Vol 76 (3) ◽  
pp. 671-678 ◽  
Author(s):  
Ross A. Widenhoefer
Keyword(s):  
Good Yield ◽  
Catalytic Amount ◽  
Outer Sphere ◽  
Deuterium Labeling ◽  
Carbon Nucleophiles ◽  
Keto Esters ◽  
Reactive Carbon ◽  
Aryl Ketones ◽  
Palladium Catalyzed ◽  
Hydride Elimination

The reaction of a 3-butenyl β-diketone with a catalytic amount of PdCl2(CH3CN)2 in dioxane at room temperature led to olefin hydroalkylation and formation of the corresponding 2-acylcyclohexanone in good yield as a single regioisomer. Deuterium-labeling experiments for the hydroalkylation of 7-octene-2,4-dione were in accord with a mechanism involving outer-sphere attack of the pendant enol on a palladium-complexed olefin to form a palladium cyclohexyl species, followed by palladium migration via iterative β-hydride elimination/addition and protonolysis from a palladium enolate complex. In comparison to a 3-butenyl β-diketone, reaction of a 4-pentenyl β-diketone with a catalytic amount of PdCl2(CH3CN)2 in the presence of CuCl2 led to oxidative alkylation and formation of the corresponding 2-acyl-3-methyl-2-cyclohexenone in good yield as a single isomer. Unactivated olefins tethered to less reactive carbon nucleophiles such as β-keto esters, α-aryl ketones, and even dialkyl ketones underwent palladium-catalyzed hydroalkylation in the presence of Me3SiCl or HCl to form the corresponding cyclohexanones in moderate-to-good yield with high regioselectivity.

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