An efficient system for the Pd-catalyzed cross-coupling of amides and aryl chlorides

A catalyst based on a new biarylphosphine ligand (3) for the Pd-catalyzed cross-coupling reactions of amides and aryl chlorides is described. This system shows the highest turnover frequencies reported to date for these reactions, especially for aryl chloride substrates bearing an ortho substituent. An array of amides and aryl chlorides were successfully reacted in good to excellent yields.     

Pd/C: An efficient and reusable catalyst for the synthesis of flavones via carbonylation of aryl halides

This work describes an efficient and mild approach for the synthesis of flavones via catalytic carbonylation of aryl halides with 2‐hydroxyacetophenone using the commercial Pd/C as an efficient, heterogeneous and recyclable catalyst. Under balloon pressure of CO, 0.6 mol% Pd/C is sufficient for moderate yields of flavones for the carbonylation of aryl iodides under phosphine‐free conditions and aryl bromides in the presence of phosphine ligand. The catalyst is easily separable and shows significant recyclability. Moreover, the reaction mechanism was discussed, and a possible mechanism that contains two different cyclisation pathways was proposed.     

Synthesis of benzoylacetonitriles from Pd-catalyzed carbonylation of aryl iodides and trimethylsilylacetonitrile

Palladium-catalyzed carbonylation of aryl iodides and trimethylsilylacetonitrile to produce benzoylacetonitrile derivatives through a one-pot, three-component reaction is described. This preparation method provides good yields of the carbonylated products without any additional ligands. It has a broad substrate scope with a high tolerance for a variety of functional groups.     

The first general palladium catalyst for the Suzuki-Miyaura and carbonyl enolate coupling of aryl arenesulfonates

The first general method for the palladium-catalyzed Suzuki-Miyaura and carbonyl enolate coupling of unactivated aryl arenesulfonates was developed utilizing XPhos, 1, and Pd(OAc)2. This is of significant interest because aryl tosylates and aryl benzenesulfonates are more easily handled and considerably less expensive than aryl triflates. This catalyst system effects the coupling of a variety of aryl, heteroaryl, and extremely hindered arylboronic acids with different aryl tosylates, under mild conditions. The same catalyst was employed in the first carbonyl enolate coupling of aryl arensulfonates.     

An efficient catalyst system for diaryl ether synthesis from aryl chlorides

The combination of 2-phosphino-substituted N-arylpyrroles or related indoles (cataCXium^®P) and Pd(OAc)₂ allows for efficient cross-coupling reactions of aryl chlorides and phenols to give diaryl ethers. A variety of aryl and heteroaryl chlorides can be coupled with substituted phenols showing unprecedented catalyst turnover numbers.     

Pd-catalyzed efficient one-pot sequential cross-coupling reactions of aryl dihalides

The palladium complex containing N-heterocyclic carbene ligands catalyzes one-pot sequential Heck/Suzuki, Heck/Heck, and Heck/Sonogashira coupling reactions of aryl dihalides to afford unsymmetrically substituted arenes in excellent yields.     

Rapid and efficient Pd-catalyzed Sonogashira coupling of aryl chlorides

An efficient and effective microwave-assisted cross-coupling of terminal alkynes with various aryl chlorides including sterically hindered, electron-rich, electron-neutral, and electron-deficient aryl chloride is developed. It proceeds faster and generally gives good to excellent yields and also can be extended successfully to the Suzuki coupling and Buchwald-Hartwig amination, as well as the Heck coupling with inert aryl chlorides. The short reaction times and simple reaction conditions coupling with a broad substrate scope render this method particularly attractive for the efficient preparation of biologically and medicinally interesting molecules.     

Carboxylic acid anhydrides via Pd-catalyzed carbonylation of aryl halides at atmospheric CO pressure

A convenient method has been developed, which allows for the direct transformation of aryl iodides into the corresponding carboxylic acid anhydrides via Pd-catalyzed carbonylation under atmospheric CO pressure.     

PdO nanoparticles supported on triazole functionalized porous triazine polymer as an efficient heterogeneous catalyst for carbonylation of aryl halides

A well‐defined triazole functionalized porous triazine based polymers act as solid heterogeneous catalyst after incorporating palladium oxide nanoparticles (PdO@TTAS) have been synthesized and thoroughly characterized by various techniques such as, FT‐IR, UV‐DRS, solid state ¹³C CP‐MAS, XPS, powder X‐ray diffraction, TGA, SEM and TEM analysis has been detailed illustrated. It is important to note that synthesized catalytic performance for carbonylation of aryl halides (X = I, Br) with EDC.HCl (N‐(3‐dimethylaminopropyl)‐N′‐ethylcarbodiimide hydrochloride), and formic acid was found to be an effective CO source in the presence of triethylamine as a base and DMF as a solvent medium at 80 °C for about 3 hr. The PdO@TTAS catalyst exhibits superior catalytic performance and along with good yield (up to 90%). Moreover, studying the heterogeneity and reusability of the environmentally friendly solid catalyst can be easily separated by simple filtration and then recycled for several times. In this reaction method, we avoided ligand, additive, promoters and CO gas, due to additional problem arise by using gaseous CO, highly toxic greenhouse gases and high pressurized reaction setup.     

A phosphine-free Pd catalyst for the selective double carbonylation of aryl iodides

The first phosphine-free Pd-catalysed double carbonylation of aryl iodides is reported as a general and practical method, giving excellent conversions and selectivities for a wide range of aryl iodides and amine nucleophiles under atmospheric CO pressure.     

Evidence for in situ catalyst modification during the Pd-catalyzed conversion of aryl triflates to aryl fluorides

A mechanistic investigation of the Pd-catalyzed conversion of aryl triflates to fluorides is presented. Studies reveal that C-F reductive elimination from a LPd(II)(aryl)F complex (L = t-BuBrettPhos or RockPhos) does not occur when the aryl group is electron rich. Evidence is presented that a modified phosphine, generated in situ, serves as the actual supporting ligand during catalysis with such substrates. A preliminary study of the reactivity of a LPd(II)(aryl)F complex based on this modified ligand is reported.     

Rapid and efficient microwave-assisted synthesis of aryl aminobenzophenones using Pd-catalyzed amination

Substituted aryl aminobenzophenone p38 MAP kinase inhibitors were synthesized in good to excellent yields using palladium-catalyzed aryl amination under conditions of microwave irradiation. Various ligands have been screened, and the reaction conditions were optimized. These coupling reactions are suitable for various anilines and aryl bromides that bear a variety of functional groups. Some leaving groups (iodides, chlorides, triflates, and tosylates) other than bromides have also been investigated. By this method, a large number of aryl aminobenzophenone p38 MAP kinase inhibitors were prepared in short order.     

Palladium-catalyzed Hiyama cross-couplings of aryl arenesulfonates with arylsilanes

Palladium-catalyzed efficient Hiyama cross-coupling reaction of aryl arenesulfonate with arylsilane is described. The desired carbon-carbon bond formation proceeds under mild conditions with good functional group tolerance.     

An improved protocol for the Pd-catalyzed alpha-arylation of aldehydes with aryl halides

An improved protocol for the Pd-catalyzed alpha-arylation of aldehydes with aryl halides has been developed. The new catalytic system allows for the coupling of an array of substrates including challenging electron-rich aryl bromides and less reactive aryl chlorides. The utility of this method has been demonstrated in a new total synthesis of (+/-)-sporochnol.     

An efficient Pd-catalyzed route to silyl esters

[formula: see text] A one-step, highly selective catalytic route to silyl esters is reported. Commercially available silanes with Si-H functionality were converted to silyl or siloxy esters in the presence of Pd(OAc)2 under mild reaction conditions. This protocol was found to be equally applicable for the modification of multiple silicon centers in one framework and lead to the corresponding polysilyl esters in high yields. A comparison of catalytic efficiency of Pd(OAc)2 versus Pd on carbon was also undertaken.     

Catalytic systems for carbonylation of aryl halides

Data on the structure and reactivity of the catalytic systems used in the synthesis of arenecarboxylic acids by carbonylation of aryl halides are summarized. Comparative analysis of the catalytic systems on the basis of palladium and cobalt complexes in terms of the mechanism of their action, range of substrates, and synthetic uses is performed. Different aspects of the cobalt-catalyzed carbonylation of aryl halides (activity of the catalytic system, reaction chemo-and regioselectivity) from the viewpoint of the radical anion mechanism of activation of aryl halides are considered.     

An efficient copper catalyst for the formation of sulfones from sulfinic acid salts and aryl iodides

[reaction: see text] A novel copper-catalyzed method for the coupling of sulfinic acid salts and aryl iodides is described. A variety of methyl and diaryl sulfones have been formed in excellent yields.     

An efficient Pd-catalyzed hydration of nitrile with acetaldoxime

An efficient palladium-catalyzed protocol for the hydration of nitrile to amide with acetaldoxime has been developed. A plausible mechanism was suggested involving the first Pd(II)-catalyzed nitrile-oxime coupling and the following disruption of the intermediate into amide and acetonitrile in a concerted manner.     

A general and efficient copper catalyst for the amidation of aryl halides

An experimentally simple and inexpensive catalyst system was developed for the amidation of aryl halides by using 0.2-10 mol % of CuI, 5-20 mol % of a 1,2-diamine ligand, and K(3)PO(4), K(2)CO(3), or Cs(2)CO(3) as base. Catalyst systems based on N,N'-dimethylethylenediamine or trans-N,N'-dimethyl-1,2-cyclohexanediamine were found to be the most active even though several other 1,2-diamine ligands could be used in the easiest cases. Aryl iodides, bromides, and in some cases even aryl chlorides can be efficiently amidated. A variety of functional groups are tolerated in the reaction, including many that are not compatible with Pd-catalyzed amidation or amination methodology.