Sonogashira Reaction Of Aryl Bromides Research Articles

Synthesis and investigation of catalytic activity of phenylene – And biphenylene bridged bimetallic Palladium-PEPPSI complexes

A series of phenylene and biphenylene-bridged N-heterocyclic carbene (NHC) and their bimetallic NHC–Pd-PEPPSI complexes were reported and fully characterized by 1H NMR, 13C NMR, HRMS, FTIR, and elemental analysis. The N tags with different electronic and steric properties were used on the synthesis of bridged bimetallic NHC–Pd-PEPPSI (PEPPSI: Pyridine Enhanced Precatalyst Preparation Stabilization Initiation) complexes. The catalytic properties of the bridged bimetallic NHC–Pd-PEPPSI complexes were investigated in the different C–C coupling reaction such as Suzuki-Miyaura reactions of aryl bromides with arylboronic acid, the Heck coupling reactions of aryl bromide with styrene and in the Sonogashira reactions of aryl bromides with phenylacetylene. Generally, all bridged bimetallic NHC–Pd-PEPPSI complexes showed good catalytic activity in the C–C coupling reactions.

Synthesis of bridged palladium-PEPPSI complexes and catalytic studies in C–C cross-coupling reactions

A series of dimetallic NHC-Pd-PEPPSI complexes with phenylene-bridged N-heterocyclic carbenes (NHC) were synthesized and fully characterized by 1H NMR, 13C NMR, HRMS, FTIR, and elemental analysis. The N tags were 2,3,4,5,6-pentamethylbenzyl, 3,5-dimethylbenzyl, 4-tert-butylbenzyl and 3-methoxybenzyl groups. The catalytic properties of the complexes were investigated in the Suzuki-Miyaura reactions of aryl bromides with arylboronic acid and in the Heck coupling reactions of aryl bromide with styrene and in the Sonogashira reactions of aryl bromides with phenylacetylene. Generally, dimetallic complexes exhibit good catalytic activities in the Suzuki-Miyaura, Heck, and Sonogashira coupling reactions.

N-heterocyclic carbene adducts of cyclopalladated ferrocenylchloropyrimidine: synthesis, structural characterization and application in the Sonogashira reaction

Three N-heterocyclic carbene (NHC) adducts of cyclopalladated ferrocenylchloropyrimidine, 2–4 [PdCl{[(η5-C5H5)]Fe[(η5-C5H3)-N2C4H2-Cl]}(NHCs)] have been prepared by reaction of the chloride-bridged palladacyclic dimer 1 [PdCl{[(η5-C5H5)]Fe[(η5-C5H3)-N2C4H2-Cl]}]2 with the corresponding imidazolium salts. These complexes were characterized by elemental analysis, IR, ESI–MS and NMR. The use of these complexes as catalysts for the Sonogashira reaction was examined. Complex 4 proved to be an efficient catalyst for the Sonogashira reaction of aryl bromides and some activated aryl chlorides under copper- and amine-free conditions. Typically, using 0.1–2 mol % of catalyst in the presence of 1.5 equivalents of CsOAc as base in dimethylacetamide at 120 °C provided coupling products in good yields.

Highly Efficient Pd/Tetraphosphine Catalytic System for Copper-Free Sonogashira Reactions of Aryl Bromides with Terminal Alkynes

In this study, an easily synthesized polydentate ligand N,N,N’,N’-tetra(diphenylphosphinomethyl)-1,2-ethylenediamine (1) in combination with [Pd(C3H5)Cl]2 was found to be an active catalyst in copper-free Sonogashira reactions. Most substrates, including steric hindered phenyl bromides and heteroaryl bromides, could couple efficiently with terminal alkynes in the presence of low catalyst loading (0.1 mol%) and this catalytic system showed excellent functional group tolerance. The influence of water in this system was also preliminarily investigated via 31P NMR in situ; that is, appropriate water favors the reaction while excess hindered this reaction. A simple ligand N,N,N’,N’-tetra(diphenylphosphinomethyl)-1,2-ethylenediamine was employed in Sonogashira reaction with relatively low catalyst loading and isolated yield up to 99 % was obtained in the absence of copper or any other additives. This catalytic system performed high efficiency and excellent functional group tolerance.

A Palladium/Perfluoroalkylated Pyridine Catalyst for Sonogashira Reaction of Aryl Bromides and Chlorides in a Fluorous Biphasic System.

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A Palladium/Perfluoroalkylated Pyridine Catalyst for Sonogashira Reaction of Aryl Bromides and Chlorides in a Fluorous Biphasic System

AbstractPalladium perfluorooctanesulfonate [Pd(OPf)2] catalyses the highly efficient Sonogashira reaction of aryl bromides and chlorides in the presence of a catalytic amount of perfluoroalkylated pyridine as a ligand in a fluorous biphasic system (FBS) composed of toluene and perfluorodecalin. The reaction can be performed under phosphane‐, copper‐ and DMF‐free conditions in an air atmosphere. By simple separation of the fluorous phase containing palladium/perfluoroalkylated pyridine catalyst, the reaction can be repeated several times.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

A Copper- and Amine-Free Sonogashira Reaction of Aryl Halides Catalyzed by 1,3,5-Triaza-7-phosphaadamantane Palladium Systems

The monomeric complex [Pd(dmba)Cl(PTA)] [dmba = N,C-chelating 2-(dimethylaminomethyl)phenyl; PTA = 1,3,5-triaza-7-phosphaadamantane] has been obtained and its crystal structure has been established by X-ray diffraction. Conditions for an efficient copper- and amine-free catalyzed Sonogashira reaction of aryl bromides and chlorides with terminal alkynes by [Pd(dmba)Cl(PTA)] and Pd(OAc)2/PTA have been developed. It is worthwhile noting that a relatively low palladium catalyst loading has been employed.

Regioselective Synthesis of 4‐Substituted‐1‐aryl‐1‐butanones Using a Sonogashira—Hydration Strategy: Copper‐Free Palladium‐Catalyzed Reaction of Terminal Alkynes with Aryl Bromides.

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Efficient Sonogashira Reactions of Aryl Bromides with Alkynylsilanes Catalyzed by a Palladium/Imidazolium Salt System

A palladium/imidazolium chloride system has been used to mediate the cross-coupling reaction of aryl halides with alkynylsilanes. The combination of 3 mol % Pd(OAc)2 and 6 mol % IMes·HCl in the presence of Cs2CO3 as base proves to be a highly efficient system in assisting coupling of aryl bromides with alkynylsilanes.

Regioselective Synthesis of 4-Substituted-1-Aryl-1-butanones Using a Sonogashira-Hydration Strategy: Copper-Free Palladium-Catalyzed Reaction of Terminal Alkynes with Aryl Bromides

A simple one-pot procedure has been developed for the synthesis of 4-substituted-l-aryl-1-butanones through copper-free Sonogashira reaction of aryl bromides with terminal alkynes in DMF under inert atmosphere, followed by the treatment with acid in the presence of oxygen. A variety of aryl bromides was reacted with 3-butyn-1-ol according to this procedure to give the expected compounds in good yield. The mechanism of the reaction and applications of the methodology are discussed.

A Copper-Free Procedure for the Palladium-Catalyzed Sonogashira Reaction of Aryl Bromides with Terminal Alkynes at Room Temperature

The catalyst system Pd2(dba)3/P(tBu)3 was found to promote the Sonogashira reaction of aryl bromides at room temperature and without CuI as the co-catalyst in high yield. The catalyst system was identified from a library of 58 potential ligands by the application of a color assay. The reaction conditions allow the use of only 0.5 mol-% palladium and ligand with reagent grade chemicals.

Pd(PhCN)(2)Cl(2)/P(t-Bu)(3): a versatile catalyst for Sonogashira reactions of aryl bromides at room temperature.

[reaction: see text] Pd(PhCN)(2)Cl(2)/P(t-Bu)(3) serves as an efficient and a versatile catalyst for room-temperature Sonogashira reactions of aryl bromides.