Palladium chloride-triphenylphosphine

Tandem cyclization of l-cyclopropylidene-5-methylenecyclooctane (233) with palladium ) chloride/triphenylphosphine in the presence of diisobutylaluminium hydride leads to the [3.3.3]propellane 235 in 74% yield by way of the proposed intermediate 234 (L = ligand) (equation 119)120. 

Hydrocarboxylation of Polyunsaturated Fatty Acids and Esters with a Palladium Chloride— Triphenylphosphine Complex Catalyst... 

Metal-catalysed cyclization is an increasingly important method of synthesis (reviews [B-4I, 2998, 3069, 3501, 3505 ). Bis(acetonitrile)dichloropalladium promotes cyclization of an alkynyl carbamate with epoxypropane and a vinyl chloride [3438] an alkynylaniline is converted into an indole by heating with a palladium chloride-triphenylphosphine catalyst [3631]. Mercury(II) acetate is an effective promotor of the cyclization of the alkenylaniline (37.2) to a reduced carbazole [3861]. 

Frankel, E.N. F.L. Thomas W.K. Rohwedder. Hydrocarboxylation of polyunsaturated fatty acids and esters with a palladium chloride-triphenylphosphine complex catalyst. Adv. Chem. Ser.1974, 13, 145-165. 

The palladium-catalyzed cross-coupling reaction featured in this procedure occurs under neutral conditions in the presence of many synthetically useful functional groups (e.g. alcohol, ester, nitro, acetal, ketone, and aldehyde). The reaction works best in N,N-dimethylformamide with bis(triphenylphosphine)palladium(ll) chloride, PdCI2(PPh3)2, as the catalyst. Lithium chloride is added to prevent decomposition of the catalyst.143 13 It is presumed that conversion of the intermediate aryl palladium triflate to an aryl palladium chloride is required for the transmetallation step to proceed.9... 

A rapid MW-assisted palladium-catalyzed coupling of heteroaryl and aryl boronic acids with iodo- and bromo-substituted benzoic acids, anchored on TentaGel has been achieved [174]. An environmentally friendly Suzuki cross-coupling reaction has been developed that uses polyethylene glycol (PEG) as the reaction medium and palladium chloride as a catalyst [175]. A solventless Suzuki coupling has also been reported on palladium-doped alumina in the presence of potassium fluoride as a base [176], This approach has been extended to Sonogashira coupling reaction wherein terminal alkynes couple readily with aryl or alkenyl iodides on palladium-doped alumina in the presence of triphenylphosphine and cuprous iodide (Scheme 6.52) [177]. 

A mixture of palladium chloride and triphenylphosphine effectively catalyzes carboxylation of linoleic and linolenic acids and their methyl esters with water at 110°-140°C and carbon monoxide at 4000 psig. The main products are 1,3-and 1,4-dicarboxy acids from dienes and tricarboxy acids from trienes. Other products include unsaturated monocar-boxy and dicarboxy acids, carbomethoxy esters, and substituted a,J3-unsaturated cyclic ketones. The mechanism postulated for dicarboxylation involves cyclic unsaturated acylr-PdCl-PhsP complexes. These intermediates control double bond isomerization and the position of the second carboxyl group. This mechanism is consistent with our finding of double bond isomerization in polyenes and not in monoenes. A 1,3-hydrogen shift process for double bond isomerization in polyenes is also consistent with the data. 

Diphenylsilane-Palladium(II) chloride-Triphenylphosphine, 126 Diphenylsilane-Tetrakis(triphenylphos-phine)palladium(0)-Zinc chloride, 126... 

Dimethylthexylsilyl trifluoromethane-sulfonate, 74 Diphenylsilane, 153 Diphenylsilane-Di- x-chlorobis(l,5-cyclooctadiene)dirhodium, 153 Diphenylsilane-Palladium(II) chloride-Triphenylphosphine, 126 Diphenylsilane-Tetrakis(triphenyl-phosphine)palladium(0)-Zinc chloride, 126... 

Methods (i) and (ii) require palladium(II) salts as reactants. Either palladium acetate, palladium chloride or lithium tetrachloropalladate(II) usually are used. These salts may also be used as catalysts in method (iii) but need to be reduced in situ to become active. The reduction usually occurs spontaneously in reactions carried out at 100 °C but may be slow or inefficient at lower temperatures. In these cases, zero valent complexes such as bis(dibenzylideneacetone)palladium(0) or tetrakis(triphenylphos-phine)palladium(O) may be used, or a reducing agent such as sodium borohydride, formic acid or hydrazine may be added to reaction mixtures containing palladium(II) salts to initiate the reactions. Triarylphosphines are usually added to the palladium catalysts in method (iii), but not in methods (i) or (ii). Normally, 2 equiv. of triphenylphosphine, or better, tri-o-tolylphosphine, are added per mol of the palladium compound. Larger amounts may be necessary in reactions where palladium metal tends to precipitate prematurely from the reaction mixtures. Large concentrations of phosphines are to be avoided, however, since they usually inhibit the reactions. 

Aryl chlorides Aryl chlorides will substitute alkenes only under very special conditions, and then catalyst turnover numbers are generally not very high. Palladium on charcoal in the presence of triethylphos-phine catalyzes the reaction of chlorobenzene with styrene,58 but the catalyst becomes inactive after one use.59 Examples employing an activated aryl chloride and highly reactive alkenes, such as acrylonitrile, with a palladium acetate-triphenylphosphine catalyst in DMF solution at ISO C with sodium acetate as base react to the extent of only 51% or less.60 Similar results have been reported for the combination of chlorobenzene with styrene in DMF-water at 130 C, using sodium acetate as the base and palladium acetate-diphos as a catalyst.61 Most recently, a method for reacting chlorobenzene with activated alkenes has been claimed where, in addition to the usual palladium dibenzilideneacetone-tri-o-tolylphosphine catalyst, nickel bromide and sodium iodide are added. It is proposed that an equilibrium concentration of iodobenzene is formed from the chlorobenzene-sodium iodide-nickel bromide catalyst and the iodoben-zene then reacts in the palladium-catalyzed alkene substitution. Moderate to good yields were reported from reactions carried out in DMF solution at 140 C 62... 

Palladium(ll) acetate, 389-392 Palladium(II) acetate-1,2-bis(diphenylphosphino)ethane, 391-392 Palladium acetate-triphenylphosphine, 392 Palladium catalysts, 392-393 Palladium(II) chloride, 393-394 Palladium(II) ehloride-eopper(I) cloride, 346 Palladium(II) chloride-silver(I) acetate, 396-397... 

Palladium, benzylchlorobis(triphenylphosphine)-, trans-, 67, 86 Palladium-catalyzed aryl-aryl coupling, 66, 70 PALLADIUM-CATALYZED ALLYLIC AMINATION, 67,105 PALLADIUM-CATALYZED CHLOROACETOXYLATION, 67, 105 PALLADIUM-CATALYZED COUPLING OF ACID CHLORIDES WITH ORGANOTIN REAGENTS, 67, 86 PALLADIUM-CATALYZED COUPLING OF ARYL HALIDES, 66, 67 PALLADIUM-CATALYZED syn-ADDITION OF CARBOXYLIC ACIDS,... 

Preformed Ethvnvlation Catalyst. Into a 500-mL round-bottomed flask equipped with a magnetic stir bar, reflux condenser and nitrogen bubbler was placed palladium chloride (1.77 g, 10 mmol), di-n-propylamine (100 mL) and triphenylphosphine (15.74 g, 60 mmol). The resulting slurry was boiled for two hr after which time the brown palladium chloride had been consumed and the yellow bis(triphenylphosphine) palladium(II) chloride had formed. The slurry was cooled and cupric acetate monohydrate (1.99 g, 10 mmol) was added in one portion and the slurry boiled for one hr longer. After cooling, the solvent was removed by rotary evaporation and then finally under high vac-... 

Palladium chloride and metallic palladium are useful for carbonylating olefinic and acetylenic compounds. Further, palladium is active for decarbonylation of aldehydes and acyl halides. Homogeneous decarbonylation of aldehydes and acyl halides and carbonylation of alkyl halides were carried out smoothly using rhodium complexes. An acyl-rhodium complex, thought to be an intermediate in decarbonylation, was isolated by the oxidative addition of acyl halide to chlorotris(triphenylphosphine)rhodium. The mechanisms of these carbonylation and decarbonylation reactions are discussed. 

Reactions of Vinylthiophens and Related Compounds. - 2-Aroyl-5-vinyl-thiophens react with triphenylphosphine, palladium chloride, and carbon monoxide to give 2-(5-aroyl-2-thienyl)propionic acid. Cycloaddition of sulphene, from methanesulphonyl chloride and triethylamine, to 2-(a-dimethylaminovinyl)thiophen gave (160). The synthesis of some substituted 3-(2-thienyl)acryloylamino-acids has been described. Some reactions of 3-chloro-j8-(2-thienyl)vinylphosphonic acid dichlorides have been studied, ... 

Alkenyl-alkenyl cross-coupling. Baba and Negishi have prepared a catalyst from this Pd(II) complex and 2 equiv. of diisobutylaluminum hydride that promotes this coupling reaction. Tetrakis(triphenylphosphine)palladium(0) is inactive, as is material prepared in situ from palladium chloride, triphenylphos-phine and HAKr-CtHg) . A nickel catalyst prepared from Ni(acac)2, PfCnHsja, and diisobutylaluminum hydride is somewhat less efficient. The coupling Involves (E)-alkenylalanes (4, 158, 159) and alkenyl halides. The products are (E,E)- and (E,Z)-dienes. 

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