172507-33-4

3-Thienylzinc bromide is prepared under mild conditions by electroreduction of a DMF solution of 3-bromothiophene, zinc bromide, and a catalytic amount of nickel-bipyridine complex using a magnesium rod as sacrificial anode. The resulting organometallic is then coupled with aryl halides using a palladium catalysis.

Thiophene-based rings are one of the most widely used building blocks for the synthesis of sulfur-containing molecules. Inspired by the redox diversity of these features in nature, we demonstrate herein a redox-divergent construction of dihydrothiophenes, thiophenes, and bromothiophenes from the respective readily available allylic alcohols, dimethyl sulfoxide (DMSO), and HBr. The redox-divergent selectivity could be manipulated mainly by controlling the dosage of DMSO and HBr. Mechanistic studies suggest that DMSO simultaneously acts as an oxidant and a sulfur donor. The synthetic potentials of the products as platform molecules were also demonstrated by various derivatizations, including the preparation of bioactive and functional molecules.

The nickel(II) pincer complex, [NiCl(PhPNP)] (PhPNP = anion of 2,5-bis(diphenylphosphinomethyl)pyrrole), has been employed as a precatalyst for the Suzuki-Miyaura cross-coupling reaction of aryl halides and boronic acids. Both electron-rich and electron-deficient aromatic bromides were found to undergo coupling with boronic acids in modest yield at elevated temperature in the presence of K3PO4·H2O. Preliminary mechanistic studies of the reaction identified a novel species formulated as the boronate complex, [Ni(OB{OH}{2-tolyl})(PhPNP)], which most likely represents a catalyst deactivation pathway. The productive catalytic cycle was found to be most consistent with a Ni(I)/Ni(III) process where the boronic acid serves as both reductant and nucleophile in the presence of base.

The invention discloses a preparing method of an aromatic nitrile or alkenyl nitrile compound. The preparing method comprises the following step that under protection of inert gas, an aryl or heteroaryl sulphonate compound shown in a formula II or an alkenyl sulphonate compound shown in a formula IV and a cyanation reagent are subjected to a cross-coupling reaction as is shown below in a solvent under the condition of the presence of a nickel complex, metal zinc and an additive to obtain the aromatic nitrile or alkenyl nitrile compound, wherein 4-dimethylamiopryidine (DMAP) is adopted as the additive, and zinc cyanide is adopted as the cyanation reagent. By means of the preparing method, cyanation of aryl sulphonate, heteroaryl sulphonate or alkenyl sulphonate can be simply and efficientlyachieved with a cheap catalysis system; moreover, the functional group compatibility and substrate universality are good, and a better application prospect and higher using value are provided for achieving industrial synthesis of the aromatic nitrile or alkenyl nitrile compound.

Palladium-catalyzed Suzuki-Miyaura cross-coupling or aryl halides is widely employed in the synthesis of many important molecules in synthetic chemistry, including pharmaceuticals, polymers and functional materials. Herein, we disclose the first palladium-catalyzed decarbonylative Suzuki-Miyaura cross-coupling of amides for the synthesis of biaryls through the selective activation of the N-C(O) bond of amides. This new method relies on the precise sequence engineering of the catalytic cycle, wherein decarbonylation occurs prior to the transmetallation step. The reaction is compatible with a wide range of boronic acids and amides, providing valuable biaryls in high yields (>60 examples). DFT studies support a mechanism involving oxidative addition, decarbonylation and transmetallation and provide insight into high N-C(O) bond activation selectivity. Most crucially, the reaction establishes the use of palladium catalysis in the biaryl Suzuki-Miyaura cross-coupling of the amide bond and should enable the design of a wide variety of cross-coupling methods in which palladium rivals the traditional biaryl synthesis from aryl halides and pseudohalides.

An efficient nickel-catalyzed cyanation of aryl sulfonates, fluorosulfonates, and sulfamates with Zn(CN)2 was developed, which provides a facile access to the nitrile products in generally good to excellent yields. The reaction is accomplished by using NiII complex as the precatalyst and DMAP as the additive. The method also displays wide functional group compatibility; for example, keto, methoxy, N,N-dimethylamino, cyano, ester, and pyridyl groups are well-tolerated during the reaction process.

Recently, oxygen-equilibrated water solutions of Kolliphor EL, a well-known surfactant, have been seen to form nanomicelles with oxygen-free cores. This has prompted the successful testing of the core environment as a green medium for palladium-catalyzed Suzuki-Miyaura cross couplings. The versatility of these conditions is endorsed by several examples, including the synthesis of relevant molecular semiconductors. The reaction medium can also be recycled, opening the way for an extremely easy and green chemistry compliant methodology.

Synthesis of photothermal agents with absorption in the near-infrared (NIR) region and featuring excellent photostability, high photothermal conversion efficiency, and good biocompatibility is necessary for the application of photothermal therapy (PTT). I

A convenient and efficient metal free borylation of aromatic amines has been achieved using tertiary butyl nitrite and B2Pin2 (bis(pinacolato)diborane) under irradiation with blue LED light at room temperature. This protocol has been successfully extended to subsequent Suzuki coupling in the same pot. Thus a series of functionalized aryl boronates and biaryls are obtained in high yields in a shorter reaction period starting from relatively cheap aryl amines in one-pot avoiding isolation of potentially unstable and hazardous intermediates.

The advent of transition-metal catalysed strategies for forming new carbon-carbon bonds has revolutionized the field of organic chemistry, enabling the efficient synthesis of ligands, materials, and biologically active molecules. In cases where a single metal fails to promote a selective or efficient transformation, the synergistic cooperation of two distinct catalysts - multimetallic catalysis - can be used instead. Many important reactions rely on multimetallic catalysis, such as the Wacker oxidation of olefins and the Sonogashira coupling of alkynes with aryl halides, but this approach has largely been limited to the use of metals with distinct reactivities, with only one metal catalyst undergoing oxidative addition. Here, we demonstrate that cooperativity between two group 10 metal catalysts - (bipyridine)nickel and (1,3-bis(diphenylphosphino)propane)palladium - enables a general cross-Ullmann reaction (the cross-coupling of two different aryl electrophiles). Our method couples aryl bromides with aryl triflates directly, eliminating the use of arylmetal reagents and avoiding the challenge of differentiating between multiple carbon-hydrogen bonds that is required for direct arylation methods. Selectivity can be achieved without an excess of either substrate and originates from the orthogonal reactivity of the two catalysts and the relative stability of the two arylmetal intermediates. While (1,3-bis(diphenylphosphino)propane)palladium reacts preferentially with aryl triflates to afford a persistent intermediate, (bipyridine)nickel reacts preferentially with aryl bromides to form a transient, reactive intermediate. Although each catalyst forms less than 5 per cent cross-coupled product in isolation, together they are able to achieve a yield of up to 94 per cent. Our results reveal a new method for the synthesis of biaryls, heteroaryls, and dienes, as well as a general mechanism for the selective transfer of ligands between two metal catalysts. We anticipate that this reaction will simplify the synthesis of pharmaceuticals, many of which are currently made with pre-formed organometallic reagents, and lead to the discovery of new multimetallic reactions.

An efficient method for synthesis of useful biaryl building blocks containing 2-thienyl, 3-thienyl, 2-pyridyl, and 3-pyridyl moieties was provided through cross-coupling reactions of aryl bromides or benzyl halides with heteroaryl aluminum reagents in the presence of Pd(OAc)2 and (o-tolyl)3P. The coupling reaction also worked efficiently with heteroaryl bromides affording series of heterobiaryl compounds. The reaction of phenylbromide with in situ prepared 3-pyridyl aluminum was demonstrated to afford the product 8a in high yield. Additionally, the catalytic system was also suited well for the coupling reaction of benzyl halides with pyridyl aluminum reagents to afford series of pyridyl-arylmethane.

A general method based on nickel-catalyzed C-O activation of various phenol derivatives with potassium (hetero)aryltrifluoroborates has been developed. A large number of heterobiaryls can be easily obtained with yields up to 99% using methanesulfonate cross-coupling partners.

A wide variety of bench-stable potassium heteroaryltrifluoroborates were prepared, and general reaction conditions were developed for their cross-coupling to aryl and heteroaryl halides. The cross-coupled products were obtained in good to excellent yields. This method represents an efficient and facile installation of heterocyclic building blocks onto preexisting organic substructures.

(Chemical Equation Presented) From chloride to boronate: Catalysts comprising palladium and biaryl monophosphine ligands provide highly active systems for the borylation of aryl and heteroaryl chlorides (see scheme). Symmetrical and unsymmetrical biaryl products can also be prepared directly from two aryl chlorides without isolation of the intermediate boronate esters. Computational studies provide insight into the roles of the biaryl phosphine ligand and the KOAc base in the catalytic cycle.

cix,cis,cis-1,2,3,4-Tetrakis(diphenylphosphinomethyl)cyclopentane/ [PdCl(C3H5)]2 efficiently catalyses the Suzuki reaction of heteroarylboronic acids with aryl bromides and also the coupling of arylboronic acids with heteroaryl bromides. The coupling of thiopheneboronic acids, 3-furanboronic acid and 3-pyridineboronic acid with a variety of aryl bromides gave the corresponding adducts in good yields. However, in most cases, better results in terms of substrate/catalyst ratio were obtained for the reaction of heteroaryl bromides with arylboronic acids. Georg Thieme Verlag Stuttgart.

R1BF3K + R2X Pd(OAc) 2 (0.5% mol)→ R1-R2 K2CO 3 (3 equiv) methanol, reflux R1 = aryl or heteroaryl R2 = aryl or heteroaryl X = halide, triflate The ligandless palladium-catalyzed Suzuki cross-coupling reaction of potassium aryl- and heteroaryltrifluoroborates with aryl- or heteroaryl halides or triflates proceeds readily with very good yields. The cross coupling can be effected in methanol or water, in the open air, using Pd(OAc)2 as a catalyst in the presence of K2CO3. A variety of functional groups are tolerated.

Couplin of organotin reagents Bu3SnAr (Ar = 2- or 3-thienyl, 2- or 3-pyridyl) with ClCOCH2CH2CO2Et in the presence of PdCl(CH2Ph)(PPh3)2 yields β-ketoesters ArCOCH2CH2CO2Et which were converted with hydrazine hydrate into 6-substituted 4,5-dihydropyridazin-3(2H)-ones, and thence to 3-halogeno-6-substituted pyridazines.The latter also couple under similar conditions with Bu3SnAr to yield 3-heteroarylpyridazines.With catalysts, coupling of ClCOCO2Et and Bu3SnAr proceeds with loss of carbon monoxide giving ArCO2Et, but without catalyst ArCOCO2Et is formed from which the3-heteroarylquinoxalin-3-one is prepared.The reactions of Bu3SnAr with 4-XC6H4Br (X = H,-OMe, -CN, -NO2) are also described.