Palladium acetate—Triphenylphosphine

The carbonylation of Af-benzyl-y-(o-bromophenyl)propylamine to give AT-benzyl-tetrahydro-2-benzazepin-l-one is catalyzed by palladium acetate-triphenylphosphine complex (78JOC1684). On treatment with 2M sodium hydroxide the aminoketone (236) undergoes ring expansion to the 2-benzazepin-l-one (237) in a manner analogous to that outlined in Scheme 28 (80HCA924). 

The bromo derivative of A -mcthylsuccinimide did also undergo Suzuki coupling when treated with naphthylboronic acid in the presence of palladium acetate, triphenylphosphine and potassium carbonate (6.3.). The coupled product was deprotected under the reaction conditions and an indole derivative was isolated in good yield, which was successfully converted into the hexacyclic naphthopyrrolo[3,4-c]carbazole structure. Using the analogous trimethylstannyl-naphthalene derivative and optimised Stille coupling conditions the desired product was isolated only in 56% yield.5... 

The TV-protected 3-amino-2-chloropyridine derivative in 7.45. for example was found to react with styrene in the presence of a palladium acetate-triphenylphosphine catalyst system at elevated temperatures to give a near quantitative yield of a single coupling product.64 In the process sodium acetate was used as base. The formation of a single regioisomer might be attributed to the steric bulk of pyridine s substituents in position 3. 

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... 

Essentially the same substituents as listed above may be present in the alkene being substituted, with the possible exception of chloro, alkoxy and acetoxy groups on vinyl or allyl carbons. These groups, especially chloro, may be lost or partially lost with palladium when the final elimination step occurs. For example, vinyl acetate, iodobenzene and triethylamine with a palladium acetate-triphenylphosphine catalyst at 100 C form mainly (E)-stilbene, presumably via phenylation of styrene formed in the first arylation step (equation 21 ).6 ... 

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... 

A further variation on this reaction is the cyclocarbonylation of hydroxy-substituted vinyl halides using a palladium acetate/triphenylphosphine catalyst system. Using this procedure five-, six- and seven-membered a-methylenelactones can be prepared (equation 43). ... 

Even simple enols have substantial lifetimes, provided that bases or acids are completely excluded173. Thus, an aromatic enol 4 is prepared in situ by Norrish-type fragmentation of 2. If (-)-ephedrine is present in the reaction mixture, the enol reverts enantioselectively to (/ )-2-rnethy 1 -1 -indanone (3). With as little as 0.01 mol % catalyst, 45% ee is obtained176. The crucial enol 4 has also been generated from either the benzyl enol ester 5 by palladium on charcoal and hydrogen or from the allyl ester 6 by palladium acetate, triphenylphosphine and ammonium formate. In the presence of a chiral 1.2-hydroxyamine, e.g., ephedrine, substantial stereogenic induction in 2-methylindanone 3 was observed175. 

A novel 2-arylation of A -substituted indoles has been reported <04OL2897>. Treatment of indole substrates with palladium acetate, triphenylphosphine, cesium acetate and aryl iodides led to the formation of 2-arylindoles. 

Dimerization of butadiene catalyzed by palladium acetate-triphenylphosphine yielded a separable mixture of octadiene acetates 59 and 60 in high yield. Acetate... 

Depending on the conditions, reducticm of a-(2-nitroaryl)acrylonitriles with carbon monoxide can give two products (Scheme 74) [194]. Thus, reduction with palladium acetate-triphenylphosphine complex (neutral conditions) leads to indole-3-carbonitriles, while in the presence of DBU or t-BuOK (basic conditions) 4-cyanoquinoline was formed. 

The reaction of 2-nitroarylacetonitriles and their heteroanalogues with trioxane has been reported to afford a-(2-nitroaryl)acrylates and their heteroanalogues, which can be reduced with carbon monoxide in the presence of palladium acetate-triphenylphosphine complex to give esters of the corresponding indole-3-carboxylic acids in high yields (Scheme 77) [193]. 

Indoles or heterocycles containing an indole skeleton were the first products to be prepared by intramolecular heterocyclic Mizoroki-Heckreaction. In 1977, the first intramolecular Mizoroki-Heck reaction was reported by Mori et al. [7], who prepared indole 3 by cyclization of (Fl-methyl 4-(N-(2-bromophenyl)acetamido)but-2-enoate (1) in the presence of palladium acetate, triphenylphosphine and iVA/ A A -tetramethylethylenediamine (Scheme 6.4). 

The palladium-catalyzed domino assembly of norbornene (65), the ds-alkenyl iodide 66, and a terminal alkyne or cyanide reported by Torii, Okumoto et al. [315] provides an example for a sequence of oxidative addition, intermolecular double bond insertion, and interception of a copper acetylide or potassium cyanide. These reactions with acetylenes have been performed in good yields in the presence of diethylamine, tetra-n-butylammonium chloride, and catalytic amounts of palladium acetate, triphenylphosphine, and copper] I) iodide. Remarkably, they are characterized by complete inversion of the cis configuration of the alkenyl iodide and a high degree of discrimination for the enantiotopic ends of the double bond in norbornene. To account for that, intermediate formation of a cyclopropylcarbinyl-palladium species by a 3-exo-trig cyclization in 67 and subsequent cycloreversion to a new homoallylpalladium intermediate as the direct precursor to 68 and 69 has been assumed. Thus, the products 68 and 69 are formed virtually with complete stereoselectivity (Scheme 8.17). 

Lecomte, R Drapier, L Dubois, Ph. Teyssie, Ph. Jerome, R. Controlled radical polymerization of methyl methacrylate in the presence of palladium acetate, triphenylphosphine, and carbon tetrachloride. Macromolecules 1997, 30, 7631-7633. 

Z)-p-iodovinylic acids or 2-iodobenzoic acids with various allenyltribulyltin reagents in the presence of palladium acetate, triphenylphosphine, and tetrabutylammonium bromide in dimethylformamide provided good yields of the corresponding ot-pyrones or 3-substituted isocoumarins via tandem Stille reaction and 6-endo-dig oxacyclization. Notably, Larock and co-workers found that isocoumarins can be produced from o/t/zo-thallated benzoic acids and olefins too. °... 

The exchange reactions of aryl or alkenyl bromides or iodides with alkenes (Scheme 26) is catalysed by a palladium acetate-triphenylphosphine catalyst in the presence... 

Disubstituted alkenes are generally less reactive towards coupling than are monosubstituted alkenes. However, the use of the more reactive aryl iodides can result in reasonable yields of the coupled product, usually as a mixture of (E) and (Z) isomers. The reaction has been applied to a coupling of 2-iodoaniline derivatives with dimethyl maleate (eq 18), the product of which spontaneously cyclizes to form quinolone derivatives in 30-70% yield. If, instead, the 2-iodoaniline is coupled with isoprene or cyclohexadiene in the presence of palladium acetate, triphenylphosphine, and triethylamine, indole and carbazole derivatives are obtained by a coupling followed by intramolecular nucleophilic attack by the heteroatom. ... 

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