Phosphine-free Palladium Complex Research Articles

Palladium‐Catalyzed Regio‐ and Stereoselective Cross‐Coupling of Baylis—Hillman Adducts and Bimetals: A Novel Method for the Synthesis of Substituted Allylsilanes and Allylgermanes.

Cross-coupling reactions between Baylis-Hillman acetate adducts and bimetallic reagents (Si−Si, Ge−Ge) catalyzed by a phosphine-free palladium complex are described. 3-Substituted-2-carbonylallylsilanes and allylgermanes were isolated in high yields. The cross-coupling reactions are regio- and stereoselective.

Palladium-Catalyzed Regio- and Stereoselective Cross-Coupling of Baylis-Hillman Adducts and Bimetals: A Novel Method for the Synthesis of Substituted Allylsilanes and Allylgermanes

Cross-coupling reactions between Baylis-Hillman acetate adducts and bimetallic reagents (Si−Si, Ge−Ge) catalyzed by a phosphine-free palladium complex are described. 3-Substituted-2-carbonylallylsilanes and allylgermanes were isolated in high yields. The cross-coupling reactions are regio- and stereoselective.

Highly regio- and stereoselective acylboration, acylsilation, and acylstannation of allenes catalyzed by phosphine-free palladium complexes: an efficient route to a new class of 2-acylallylmetal reagents.

A new method for the synthesis of substituted 2-acylallylmetal reagents in a highly regio- and stereoselective fashion involving a three-component assembly of allenes, acyl chlorides, and bimetallic reagents (B-B, Si-Si, and Sn-Sn) catalyzed by phosphine-free palladium complexes is described. Treatment of various allenes (CR(2)R(3)=C=CH(2)) with acyl chlorides (R(1)COCl) and bispinacolatodiboron in the presence of PdCl(2)(CH(3)CN)(2) in toluene at 80 degrees C gave 2-acylallylboronates in moderate to good yields. The acylsilation of allenes with acid chlorides and hexamethyldisilane (5) proceeded successfully in the presence of Pd(dba)(2) in CH(3)CN affording the corresponding allylsilanes (CR(2)R(3)=C(COR(1))CH(2)SiMe(3)) in good to moderate yields. Several chloroformates (R(4)OCOCl) also react with 1,1-dimethylallene (2a) and 5 to afford allylsilanes (CR(2)R(3)=C(COOR(4))CH(2)SiMe(3)) in 66-70% yields. Acylstannation of allenes could also be achieved by slow addition of hexabutylditin (10) to the reaction mixture of acyl chloride (or chloroformate) and allene 2a in CH(3)CN in the presence of Pd(dba)(2) at 60 degrees C; the corresponding 2-substituted allylstannanes were isolated in moderate to good yields. The above catalytic reactions are completely regioselective and highly stereoselective. A mechanism is proposed to account for the catalytic reactions and the stereochemistry.

Palladium-Catalyzed, Atmospheric Pressure Carbonylation of Allylic Halides under the Influence of Sodium Hydroxide or Alkoxides. A Facile Synthesis of β,γ-Unsaturated Acids

Abstract The palladium-catalyzed, atmospheric-pressure carboxylation of allylic halides occurs readily in an aqueous sodium hydroxide/organic solvents two-phase system, giving β,γ-unsaturated acids. Phosphine complexes [PdCl2L2] (I, L = m-(Ph2P)C6H4SO3Na; II, L = Ph3P) or Na2[PdCl4] (III) can be used as the catalyst. Atmospheric-pressure alkoxycarbonylation is realized under the influence of a homogeneous alcoholic solution of sodium alkoxide. Phosphine-free palladium complexes, such as [(π-allyl)PdCl]2 or III, are the favored catalyst. β,γ-Unsaturated esters are obtained in high yields.

Cyclodimerization of butadienes catalyzed by phosphine-free palladium complexes

Les especes Pd(0) sans phosphine produites par decomposition a basse temperature de complexes bis-allyl Pd(II) sont de bons catalyseurs pour la cyclodimerisation des dienes