Palladium acetate catalyst

A methyl group can be introduced into an aromatic ring by treatment of diazonium salts with tetramethyltin and a palladium acetate catalyst." The reaction has been performed with Me, Cl, Br, and NO2 groups on the ring. A vinylic group can be introduced with CH2=CHSnBu3. 

Figure 5.26 Catalytic activity of a UV-decomposed palladium acetate catalyst. Nitrobenzene conversion ( ) aniline selectivity ( ) [60].

Under optimum reaction conditions (See Table IV.), selectivity to linear dimer is controlled by the choice of temperature, solvent and tertiary phosphine. Toluene and tetrahydrofuran are the best solvents. Temperatures between 25 to 60 C with a triphenyl or tributylphosphine/palladium acetate catalyst give linear dimer selectivities in the 80 s. At 25 C in toluene, a palladium acetate/tributylphosphine catalyst gave 98.7% conversion and 89.6% linear, 4.7% branched, 1.9% cyclic, and 3.8% heavies selectivity. The linear dimerization reaction was second order in diene with a 3.6 Kcal/mole activation energy. 

Vinyl ethers yield acylated vinyl ethers when they are reacted with aroyl chlorides or 3-thienylcarbo-nyl chloride, triethylamine and a palladium acetate catalyst at 60-70 C (equation 43).103 The products of this reaction are useful 1,3-dicaibonyl equivalents. At higher temperatures the reaction yields arylated vinyl ethers. It is interesting that the acylations of vinyl ethers are regioselective while the direct aryla-tions are usually not.104... 

Baeyer-Villiger m-Chloroperbenzoic acid. benzylic Palladium acetate. catalyst Platinum. 

Reduction of aromatic nitro groups using triethylammonium formate, catalyzed by pal-ladium-on-carbon or a soluble triaryphosphine-palladium acetate catalyst is compatible with ester or amide functions, leading to a-amino esters . The nitro group of the pyra-none 2 is selectively reduced, without hydrogenolysis of the benzyl ether linkage in the presence of finely divided Ni ° ... 

O/t/20-arylation of benzoic acids is often preferable to ortho-arylation of benzamides if conversion of the amide moiety to other functional groups is desired. However, only a few reports have dealt with the orf/io-functionalization of free benzoic acids due to challenges that involve such transformations. The reactions can be complicated by decarboxylation of the product and the starting material. Despite those difficulties, several methods for direct o/t/io-arylation of benzoic acids have been developed. Yu has shown that arylboronates are effective in arylation of benzoic acids under palladium catalysis [59], The reactions require the presence of palladium acetate catalyst, silver carbonate oxidant, and benzoquinone. Even more interestingly, the procedure is applicable to the arylation of unactivated sp3 C-H bonds in tertiary carboxylic acids such as pivalic acid (Scheme 13) if aryl iodide coupling partner is used. Aryl trifluoroborates can also be used [60],... 

R, and ligands on the palladium, and the dominance of meta over para substitution is an electronic effect of the substituent on the cleaving carbon—hydrogen bond. In a variation of the Heck reaction, it has been shown that arylsulfinic acids may be substituted by alkenes in the presence of a palladium acetate catalyst, with copper... 

As organosulfur compounds have been widely believed to be catalyst poisons, examples of the transition metal catalyzed reaction of these sulfur compounds have been limited. After the development of transition metal catalyzed addition of organosulfur compounds such as disulfides and thiols to carbon-triple bonds [9], many types of transition metal catalyzed addition reactions of organosulfur compounds have been developed. As to allenes, for example, the addition of thiols to terminal allenes successfully proceeds regioselectively at the internal double bonds of the allenes by the action of palladium acetate catalyst [10a,10b], while the disulfide addition to terminal allenes takes place at the terminal double bond in the presence of tetrakis (triphenylphosphine) palladium catalyst (Scheme 11.6) [10c]. 

The acetoxylation of arenes tethered to 3,4-dihydroisoquinoline has been achieved using phenyliodonium acetate and acetic anhydride with a palladium acetate catalyst. 

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