Alcohols palladium® acetate

The method is basically an application of the Wacker oxidation except that the catalyst used is palladium acetate ( Pd(AcO)2 or Pd(02CCH3)2). the solvent is acetic acid or tert-butyl alcohol and the oxygen source is the previously suggested hydrogen peroxide (H202)[17]. 

Allylphosphonium salts are synthesized by substitution of allyl halides with PPh3. The use of allyl alcohol, allyl acetate, or nitropropene with a palladium catalyst has also been reported.19 It is shown in this study that the organophosphorous compounds can be obtained by a palladium-catalyzed addition to an allene. A notable aspect of this method is that it can control the stereochemistry of the phosphonium salt, and that (Z)-allylphosphonium salts have been obtained in pure form for the first time. 

In analogy with the oxybromination reaction of allenyl alcohols, allenyl acids 12 afforded five- and six-membered lactones 13 on treatment with lithium bromide in the presence of palladium acetate (Scheme 17.8) [7, 8],... 

The iodo acetal could be easily obtained (as a mixture of E and Z isomers, 40/60), by a nickel catalyzed iodine-bromine exchange. This synthon reacted smoothly with the C15 tertiary allylic alcohol in the presence of a catalytic amount of palladium acetate and a stoechiometric amount of either a silver or a thallium salt. The C20 hydroxy-acetal was obtained in 38% yield, as a mixture of E and Z isomers (48/52). Finally retinal was obtained by treatment with dilute HBr in refluxing acetone, as a mixture of E and Z isomers (C(9)=C(io) and C(i3)=C(i4)), Fig. (32). 

Palladium alkoxide complexes are thought to be formed in the reactions of alcohols catalyzed by palladium(II) chloride. These reactions include the oxidation of alcohols, yielding acetals or ketones,137,138 and their carbonylation, yielding esters.139 Alkoxide intermediates are also thought to be involved in the reaction of sulfur dioxide with [PdCl2] suspended in alcohol (equation 15).140,141... 

Mixtures of regioisomers are frequendy obtained in these reactions.80 The problem is most serious with primary allylic alcohols without a- or p-substituents. Even the 2-arylated products generally rearrange to saturated aldehydes. Ally alcohol itself, when reacted with iodobenzene and triethylamine, with palladium acetate as catalyst, for example, produces a 71 % yield of an 84 16 mixture of 3-phenyl- and 2-phenyl-propanal (equation 28). 

Oxidative coupling of N-benzoylpyrroles was achieved with palladium acetate. From a reaction at 110°C in acetic acid, benzopyrrolizinones (35) and 2,2 -dimeric compounds (36) were obtained. Under the same conditions 1-aroylindoles gave 37 and 38 but no 2,2 -dimeric compounds.30 Treatment of dibenzoylpyrrolizinones (37) with potassium t-butoxide/f-butyl alcohol containing a small amount of water at 82°C afforded o-(2-indo yI)benzoic acids in good yield.31... 

Kindler et al. hydrogenated a-hydroxyiminoacetophenone and a-hydroxyimino-propiophenone (eq. 8.26) to the corresponding phenylalkylamines over a palladium black in acetic acid in the presence of sulfuric acid.51 The hydrogenolysis of the intermediate amino alcohols proceeded not at all in alcohol and acetic acid, and only rather slowly in acetic acid-sulfuric acid. In contrast, 3 -hydroxy-3 -phenylpropylamine, with one more carbon atom between the hydroxyl and amino groups, was hydrogenolyzed much faster under these conditions. Perchloric acid may also be used instead of sulfuric acid, but some hydrogenation of the aromatic ring occurred even when the hydro-... 

The reaction of allylic alcohols and aryl halides in the presence of a palladium catalyst has been used in the past to prepare various 0-arylal-dehydes. The procedure described here is essentially that of Heck and Melpolder.3 A similar reaction has been carried out with bromobenzene and 2-methyl-2-propen-l-ol in hexamethylphosphoric triamide (HMPT) as solvent with sodium bicarbonate as base. A variety of other bases have also been used.4 2-Methyl-3-phenylpropanal has been prepared by reacting palladium acetate and phenylmercuric acetate with 2-methyl-2-propen-l-ol.5... 

Tris(3-sulphonatophenyl) phosphine tetrahydrate sodium salt (42 mg) and palladium ) acetate (18 mg) were mixed in 2 ml water for 1 hour at ambient temperature, then treated with the Step 2 product (0.7 mmol), and 4-chloro-( ,)-cinnamyl acetate (0.5 mmol) dissolved in 2 ml acetonitrile. The mixture was stirred 90 minutes at 50°C and was then cooled to ambient temperature and diluted with water. It was then extracted several times with CH2C12 and extracts dried and concentrated. The residue was purified by chromatography using CH2Cl2/methyl alcohol, 90 10, and 154 mg product isolated. 

Three-component additions, comprising two conjugated diene molecules and a nucleophile, can be catalyzed by palladium salts, such as palladium acetate. The major products are 1-substituted 2,7-octadienes, along with minor amounts of 3-substituted 1,7-octadienes (equation 65). Water, alcohols, phenols, carboxylic acids, and amines are some of the nucleophiles that have been used in this reaction. 

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