Palladium compound

Palladium slurries react with a variety of aryl halides and result in trans-[P(C2H5)3]2Pd(R)X compounds. The trans geometry for all these compounds was established by NMR spectroscopy [14]. In general, increased temperatures 

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Palladium Compounds, Complexes, and Ligands Widely Used in Organic Synthesis... 

J. Tsuji. Organic Synthesis with Palladium Compounds, Springer. Berlin. 1980. 

Water hydroly2es pure diketene only slowly to give acetoacetic acid [541-50-4] which quickly decomposes to acetone and carbon dioxide, but increasing the pH or adding catalysts (amines, palladium compounds) increases the rate of hydrolysis. The solvolysis of diketene in ammonia results in aceto acetamide [5977-14-0] if used in stoichiometric amounts (99), and P-arninocrotonarnide [15846-25-0] if used in excess (100). 

Other useful references are R. E. Heck, Palladium Reagents in Organic Synthesis Academic Press, New York, 1985, and J. Tsuji, Organic Synthesis with Palladium Compounds, Sptinger-Vedag, New York, 1980. 

Oxiranes have been isomerized by palladium compounds to allylic alcohols and enones (79JA1623), and to 1,3-diketones (80JA2095). 

PdF2 is that rare substance, a paramagnetic palladium compound, explicable in terms of (distorted) octahedral coordination of palladium with octahedra sharing corners [15], It exists in two forms, both having /zeff 2.0 /xB, rather below the spin only value for two unpaired electrons. Bond lengths are Pd-F 2.172 A (two) and 2.143 A (four) in the tetragonal form (rutile structure). 

Electrochemical reduction of ci 5,-PtCl2(PR3)2 (R = Ph, Et) generates very reactive Pt(PR3)2 species [51] (though it has been suggested that corresponding palladium compounds may be anionic, e.g. Pd(PR3)2Cl2 )... 

The palladium compound [Pd(CNcy)2]3 has been made by metal vapour synthesis, from Pd atoms and a solution of cyNC at 160 K. It has an analogous structure [Pd3(CNcy)3( 2-CNcy)3] [60]. 

Palladium(V) complexes, 5, 1100 Palladium compounds photothermography, 6, 118 Palladium dichloride solid state oligomerization, 1, 187 Palladium(II) salts sensitizers... 

When the Pd bears chiral ligands, these reactions can be enantioselective. TT-Allylmolybdenum compounds behave similarly.Because palladium compounds are expensive, a catalytic synthesis, which uses much smaller amounts of the complex, was developed. That is, a substrate such as an allylic acetate, carbo-... 

Secondary amines can be added to certain nonactivated alkenes if palladium(II) complexes are used as catalysts The complexation lowers the electron density of the double bond, facilitating nucleophilic attack. Markovnikov orientation is observed and the addition is anti An intramolecular addition to an alkyne unit in the presence of a palladium compound, generated a tetrahydropyridine, and a related addition to an allene is known.Amines add to allenes in the presence of a catalytic amount of CuBr " or palladium compounds.Molybdenum complexes have also been used in the addition of aniline to alkenes. Reduction of nitro compounds in the presence of rhodium catalysts, in the presence of alkenes, CO and H2, leads to an amine unit adding to the alkene moiety. An intramolecular addition of an amine unit to an alkene to form a pyrrolidine was reported using a lanthanide reagent. 

Addition-elimination reactions of palladium compounds with olefins... 

Organomercurial carbonylation. Use of Co2(CO)g as a stoichiometric and as a catalytic reagent Organic synthesis reactions using palladium compounds Decarbonylation reactions using transition metal compounds... 

Some care must be taken in drawing conclusions from the E/Z or syn/anti selectivity of a given catalyst/alkene combination. The intrinsic stereoselectivity may be altered in some cases by subsequent isomerizations initiated by the catalyst. For example, epimerization of disubstituted vinylcyclopropanes is effectively catalyzed by palladium compounds the cis - trans rearrangement of ethyl chrysanthemate or of chrysanthemic acid occurs already at room temperature in the presence of PdCl2 L2 (L = MeCN, EtCN, PhCN)96 Oxycyclopropane carboxylic esters undergo metal-... 

The diimine palladium compounds are less active than their nickel analogs, producing highly branched (e.g., 100 branches per 1,000 carbons) PE. However, they may be used for the copolymerization of Q-olefins with polar co-monomers such as methyl acrylate.318,319 Cationic derivatives, such as (121), have been reported to initiate the living polymerization of ethylene at 5°C and 100-400 psi.320 The catalyst is long-lived under these conditions and monodisperse PE (Mw/Mn= 1.05-1.08) may be prepared with a linear increase in Mn vs. time. 

The copolymerization of carbon monoxide and a-olefins is one of the most challenging problems in polymer synthesis. Sen and his coworkers discovered that some cationic palladium compounds catalyze this alternative copolymerization, giving polyketones (Eq. 13). 

Reaction of organic halides with alkenes catalyzed by palladium compounds (Heck-type reaction) is known to be a useful method for carbon-carbon bond formation at unsubstituted vinyl positions. The first report on the application of microwave methodology to this type of reaction was published by Hallberg et al. in 1996 [86], Recently, the palladium catalyzed Heck coupling reaction induced by microwave irradiation was reported under solventless liquid-liquid phase-transfer catalytic conditions in the presence of potassium carbonate and a small amount of [Pd(PPh3)2Cl2]-TBAB as a catalyst [87]. The arylation of alkenes with aryl iodides proceeded smoothly to afford exclusively trans product in high yields (86-93%) (Eq. 61). 

Another easily available palladium compound is PdCl2 however, it has low or no activity. The chloride ion in the coordination sphere of palladium seems to inhibit the coordination of two moles of butadiene to form the bis-77-allylic complex. However, PdCl2 can be used in the presence of an excess of bases, such as KOH, NaOH, sodium phenoxide, sodium acetate, potassium acetate, sodium methoxide, or tertiary amines. These bases deprive the chloride ion from the coordination sphere of palladium to form the active species. Thus, very stable and easily prepared... 

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