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The study describes a new, efficient and reusable [Cu.sub.2O]/[PPh.sub.3]/TBAB system for the cross-couplings of aryl halides and heteroaryl halides with terminal alkynes. The system has been proved to be extremely efficient, as it can be recovered and reused several times.

A CuI/DABCO system was developed for the cross-coupling reactions of aryl halides and vinyl halides. It was found that the CuI/DABCO catalytic system was effective for Sonogashira cross coupling of aryl halides and vinyl halides.

An efficient method for palladium-catalyzed homocoupling reaction of terminal alkynes in the synthesis of symmetric diynes is presented. The results showed that both Pd(OAc)2 and CuI played crucial roles in the reaction.

Reusable copper-catalyzed cross-coupling reactions of aryl halides with organotins in inexpensive ionic liquids were examined. It was found that in the presence of Cu2O nanoparticles and P(o-tol)3, a variety of aryl halides including aryl chlorides underwent the Stille reaction with organotins smoothly in moderate to excellent yields in TBAB medium.

PdCl2(PPh3)2 combined with TBAF under solvent-free conditions provided general and fast Sonogashira cross-coupling reactions of aryl halides with terminal alkynes. In the presence of 3 mol % of PdCl2(PPh3)2 and 3 equiv of TBAF, a number of ArX species were coupled with alkynes to afford the corresponding products in moderate to excellent yields under copper, amine and solvent-free conditions.

An efficient Pd(OAc)(sub 2)/Dabco-catalyzed Stille cross-coupling reaction procedure is developed. In the presence of Pd(OAc)(sub 2) and Dabco (triethylenediamine), various aryl halides including aryl iodides, aryl bromides, and activated aryl chlorides are coupled efficiently with organotin compounds to afford the corresponding biaryls, alkene, and alkynes in good to excellent yields.

A novel PdX2- catalyzed dimerization of alkynes providing efficient, highly regio-and stereoselective route to synthesize symmetrical (1Z,3Z)-1,4-dihalo-1,3-dienes was developed. The effect of solvent had a fundamental influence on the chemoselectivity of the dimerization reactions.

Palladium-catalyzed cross-coupling reaction of terminal alkynes with arylboronic acids is described and a variety of terminal alkynes have undergone the reaction with numerous boronic acids in the presence of Pd[(OAc).sub.2] and [Ag.sub.2]O. This method is applied for preparing 1H-isochromenes and diynes and the reaction has proceeded under ligand-free and relative lower loading Pd conditions and the maximal TONs (turnover numbers) of the reactions are up to 720,000.

Efficient and solvent-free copper-catalyzed N-arylations of imidazoles with aryl and heteroaryl halides are demonstrated. A variety of imidazoles underwent the N-arylation reaction with aryl and heteroaryl halides smoothly in moderate to excellent yields in the presence of CuBr, 2-aminopyrimidine-4,6-diol and TBAF (n-[Bu.sub.4]NF).

A stable and efficient Pd(OAc)(sub 2)/PABCO (triethylenediamine) catalytic system or Suzuki-Miyaura cross-coupling reaction is developed. A number of aryl halides, including aryl iodides, bromides, and chlorides are coupled with arylboronic acids smoothly and efficiently to produce good to excellent yields and high turnover numbers (TONs) in the presence of this catalytic system.

A general and selective palladium-catalyzed carbonylation of terminal alkynes method for the synthesis of (Z)-3-haloacrylates is presented. The result showed the effect of solvent had a fundamental influence on the chemoselectivity and stereoselectivity of the palladium-catalyzed carbonylation reaction.

The role of Carbon dioxide (CO2) to promote the Palladium-Catalyzed (Pd)/C zinc-mediated reductive, is presented. Aromatic halides including less reactive aromatic chlorides are coupled in the presence of (CO2), Pd/C, and zinc, to give the corresponding homocoupling products in good yields.

A new copper-catalyzed intermolecular 1,2-aminoalkylation of alkenes with α-bromoalkyl esters and amines for the synthesis of γ-amino esters is described. Employing the Cu(OTf)2 and 2,2'-bipyridine catalytic system, the three-component reaction allows the formation of two new chemical bonds, including one C-C bond and one C-N bond, in a single reaction, and represents a new alkene difunctionalization using a radical strategy. [ABSTRACT FROM AUTHOR]

A new silver-promoted oxidative ring opening/alkynylation of cyclopropanols with ethynylbenziodoxolones (EBX) is described. This method enables the formation of alkylated alkynes via a sequence of ring opening and alkynylation. Control experiments support a radical mechanism in this silver-promoted method. [ABSTRACT FROM AUTHOR]

A new 1,4-diazabicyclo[2.2.2]octane (DABCO) mediated synthesis of malonates from 3-halopropynoates, alcohols, and water is presented. This method proceeds under mild and metal-free conditions, and represents a new straightforward access to 1,3-dicarbonyl compounds. [ABSTRACT FROM AUTHOR]

Oxindoles are an important class of heterocycles with unique biological activity that are found prevalently in numerous natural products and biologically active compounds. For these reasons, much attention has been given to the development of efficient methods for the preparation of such compounds. Traditionally, the practical approaches for the synthesis of oxindoles include the condensation of anilines with carbonyl compounds, such as diethyl ketomalonate, oxalyl chloride, or chloral hydrate, mediated by strong acids or bases. Recently, a step- and atom-economic C-H activation strategy was illustrated to access oxindoles through the difunctionalization of activated alkenes for these purposes. However, many of these transformations suffer from the cost of the transition-metal catalytic systems and/or limited substrate scope. In this review, we describe the recent studies of the difunctionalization of activated alkenes for the synthesis of diverse functionalized oxindoles that involves C-H oxidative radical coupling in the presence of an oxidant. These transformations are initiated either by the carbon radical resulting from the split of the carbon-hydrogen bond (1,2-dicarbofunctionalization) or by the carbon or heteroatom radical arising from the cleavage of the carbon-heteroatom (1,2-dicarbofunctionalization) or heteroatom-heteroatom bond (1,2-carboheterofunctionalization). Importantly, these C-H oxidative radical coupling transformations are generally performed with readily available oxidants and/or inexpensive iron or copper catalysts under neutral reaction conditions. 1 Introduction 2 Synthesis of Oxindoles via 1,2-Dicarbofunctionalization of Alkenes 2.1 1,2-Alkylarylation 2.2 1,2-Aryltrifluoromethylation 2.3 1,2-Carbonylarylation 3 Synthesis of Oxindoles via 1,2-Carboheterofunctionalization of Alkenes 3.1 1,2-Azidoarylation or 1,2-Arylnitration 3.2 1,2-Arylsulfonylation 3.2 1,2-Arylphosphorylation 4 Conclusion [ABSTRACT FROM AUTHOR]

A novel Lewis acid catalyzed annulation reaction has been established for the synthesis of benzocydohepta[b]indoles. This method represents a new annulation strategy to a seven-membered carbocydic ring system from two 3-(1H-isochromen-1-yl)-1H-indole molecules using Cu(OTf)2 catalyst; moreover, the products, benzocydohepta[b]indoles, can be used as the rapid mercuric ion colorimetric detection reagents. [ABSTRACT FROM AUTHOR]

A new, simple, base-mediated addition reaction of 1,2-bis(phenylsulfonyl)ethane to ketones has been developed for the synthesis of 1-aryl-4-(phenylsulfonyl)butan-1-ones. This method represents the first example of preparing sulfones using 1,2-bis(phenylsulfonyl)ethane as the sulfone resource. [ABSTRACT FROM AUTHOR]

A new, practical, base-mediated method has been developed for the synthesis of 2,4-bis(aryloxy)-1,5-diarylpentane-1,5-diones by a tandem α-methylenation-Michael reaction through activation of two C-Cl bonds. This method permits the use of dichloromethane instead of dibromomethane as a source of one carbon atom for the α-methylenation reaction. The products are useful in syntheses of polysubstituted pyridines and methylenebisbenzofurans. [ABSTRACT FROM AUTHOR]

Ligand-free palladium-catalyzed Suzuki-Miyaura crosscoupling of iodoethynes with arylboronic acids under aerobic conditions has been developed. In the presence of palladium(II) acetate and cesium carbonate, a variety of iodoethynes underwent the Suzuki-Miyaura cross-coupling reaction with arylboronic acids at room temperature to afford the corresponding internal alkynes in moderate to good yields. It is noteworthy that this protocol proceeds under mild and aerobic conditions without the aid of ligands. [ABSTRACT FROM AUTHOR]

An efficient and copper-free palladium-catalyzed Sonogashira cross-coupling reaction protocol is presented. In the presence of 3 mol% of Pd(OAc)2 and 6 mol% of DABCO, cross-coupling of various aryl halides (iodides and bromides) with terminal alkynes afforded the corresponding alkynes in moderate to excellent yields. Moreover, high TONs (turnover numbers, up to 720 000 for the reaction of 1-iodo-4-nitrobenzene with phenylacetylene) for the Sonogashira cross-coupling reaction were observed. [ABSTRACT FROM AUTHOR]

The first example of molecular sieve-promoted TBHP-mediated direct oxidative thiolation of an sp3C–H bond adjacent to a nitrogen atom with disulfides under metal-free conditions, which allows for preparation of numerous S,N-containing compounds, is presented. Moreover, diverse benzothiazoles and a fipronil analog can be synthesized through this strategy. [ABSTRACT FROM AUTHOR]

PdCl2(PPh3)2 combined with TBAF under solvent-free conditions provided general and fast Sonogashira cross-coupling reactions of aryl halides with terminal alkynes. In particular, this protocol could be applied to the reactions of deactivated aryl chlorides. In the presence of 3 mol % of PdCl2(PPh3)2 and 3 equiv of TBAF, a number of ArX species (X = I, Br, Cl) were coupled with alkynes to afford the corresponding products in moderate to excellent yields under copper-, amine-, and solvent-free conditions. [ABSTRACT FROM AUTHOR]