Palladium-catalyzed Suzuki-Miyaura Cross-coupling Reaction Research Articles

The synthesis of novel directly conjugated zinc(II) phthalocyanine via palladium-catalyzed Suzuki–Miyaura cross-coupling reaction and its quaternized water-soluble derivative: Investigation of photophysical and photochemical properties

The novel zinc(II) phthalocyanine directly conjugated with 4-(diethylamino)phenyl groups (2) via CC bond formation using Suzuki-Miyaura coupling reaction was synthesized for the first time. This phthalocyanine was converted to the quaternized derivative (3) to enhance its water solubility. The photochemical (singlet oxygen quantum yield and photodegradation quantum yield) and photophysical (fluorescence quantum yield and lifetime) properties of the synthesized novel zinc(II) phthalocyanines (2 and 3) were investigated in DMSO (for both phthalocyanines 2 and 3) and in aqueous solution (for only phthalocyanine 3) for determination of their photodynamic therapy abilities. Additionally, the bovine serum albumin (BSA) binding behavior of the water soluble zinc(II) phthalocyanine (3) was investigated in aqueous solution for determination of transporting capability of this phthalocyanine in the circulatory system.

Indazolium halides as efficient ligands for Pd-catalyzed Suzuki–Miyaura cross-coupling of aryl bromides with arylboronic acids

The indazolium halides containing various N-substituents have been conveniently prepared and applied in the palladium-catalyzed Suzuki–Miyaura cross-coupling reactions of aryl bromides with arylboronic acids at mild reaction conditions. The cross-coupling reaction provides the desired products in good to high yields. The ease of synthesis and the modularity, and the broad range of aryl bromides and arylboronic acids make this type of ligand attractive and promising for transition metal catalysis.

ChemInform Abstract: Recent Advances in the Palladium Catalyzed Suzuki‐Miyaura Cross‐Coupling Reaction in Water

AbstractReview: 112 refs.

Recent Advances in the Palladium Catalyzed Suzuki–Miyaura Cross-Coupling Reaction in Water

The palladium-catalyzed Suzuki–Miyaura cross-coupling reaction of organic halides with boronic acids is one of the most versatile methods for the synthesis of biaryls. Green chemistry is a rapidly developing new field that provides us a proactive avenue for the sustainable development of future science and technologies. When designed properly, clean chemical technology can be developed in water as a reaction medium. The technologies generated from such green chemistry endeavours may often be cheaper and more profitable. This review covers the literature on palladium-catalysed the Suzuki–Miyaura cross-coupling reaction in water.

Heteroatom-substituted secondary phosphine oxides for Suzuki-Miyaura cross-coupling reactions

Several di-substituted diimines (3a–3f) and heteroatom-substituted unsaturated secondary phosphine oxides (HASPO, 6a–6f) were prepared and characterized. Compounds 6a–6f are regarded as pre-ligands because of their ability of tautomerization to heteroatom-substituted phosphinous acid (HAPA, 7a–7f). An unexpected 3e-coordinated palladium dibromide 8e was observed from the reaction of compound 6e with PdBr2. Molecular structures of pre-ligands 6a, 6c, and 6e, as well as palladium complexes 8e were determined by single crystal X-ray diffraction methods. When pre-ligand 6a was applied to palladium-catalyzed Suzuki-Miyaura cross-coupling reactions, satisfactory yields were obtained. Density functional theory were employed to examine the electronic properties of HASPO 6a–6f pre-ligands, their corresponding 1,3-di-N-substituted tautomers 7a–7f, and the saturated counterpart 7as of 7a. Compound 7a is the most effective and genuine ligand in Suzuki-Miyaura reaction that is confirmed by its higher-lying lone-pair (LP) molecular orbital (HOMO-1). The LP orbital of 7c–7f is lower-lying HOMO-5. For each 7c–7f, two conformational rotamers with minute energy difference were located. Hirshfeld charge and population analysis of 7c–7f were also calculated in order to comprehend the electronic properties for these two rotamers for each HAPAs. Besides, the steric effect of HAPAs was estimated in terms of the Percent Buried Volume (%Vbur). This model has shown that 7a has similar steric property to that of PCy3, which is an effective ligand in Suzuki-coupling reactions.

Synthesis and photophysical properties of tetra and pentaarylated fluorobenzenes

Novel difluoro-tetraaryl and monofluoro-pentaarylbenzenes were prepared by palladium-catalyzed Suzuki–Miyaura cross-coupling reactions of novel 1,2- and 1,4-difluorotetraiodobenzene and of 1-fluoropentaiodobenzene. These Suzuki–Miyaura reactions allowed a convenient synthesis of fluoro-substituted aryl benzenes. The photophysical properties (absorption and fluorescence) of the products have been studied.

Postsynthetic modification of peptoids via the Suzuki-Miyaura cross-coupling reaction.

We developed a new method for modifying the side chains of peptoids on a solid phase resin, employing the palladium-catalyzed Suzuki-Miyaura cross-coupling reaction. Optimized conditions using Pd(PPh3 )4 and K2 CO3 in the presence of Buchwald's SPhos ligand provided a high conversion in the coupling reaction. The usefulness of this method was demonstrated by synthesis of a two pyrene-conjugated peptoid helix, which exhibited an interesting excimer formation.

Imidazolin-2-ylidenaminophosphines as Highly Electron-Rich Ligands for Transition-Metal Catalysts.

A variety of chemical transformations benefit from the use of strong electron-donating ancillary ligands, such as alkylphosphines or N-heterocyclic carbenes when electron-rich metal centers are required. Herein, we describe a facile and highly modular access to monodentate and bidentate imidazolin-2-ylidenamino-substituted phosphines. Evaluation of the phosphine's electronic properties substantiate that the formal replacement of alkyl or aryl groups by imidazolin-2-ylidenamino groups dramatically enhance their donor ability beyond that of alkylphosphines and even N-heterocyclic carbenes. The new phosphines have been coordinated onto palladium(II) centers, and the beneficial effect of the novel substitution patterns has been explored by using the corresponding complexes in the palladium-catalyzed Suzuki-Miyaura cross-coupling reaction of non-activated aryl chloride substrates.

ChemInform Abstract: N‐Methyliminodiacetic Acid as a Simple and Highly Efficient Ligand for Palladium‐Catalyzed Suzuki—Miyaura Cross‐Coupling of Aryl Chlorides.

A simple, air-stable, inexpensive and easily prepared molecule, N-methyliminodiacetic acid (MIDA), is reported as a ligand for palladium-catalyzed Suzuki–Miyaura cross-coupling reaction of phenylboronic acid with aryl chlorides. The yield of the corresponding Suzuki coupling reaction is up to around 90% at both high temperature of 80°C and room temperature under ambient atmosphere. Copyright © 2015 John Wiley & Sons, Ltd.

A convenient synthesis of 4(5)-(hetero)aryl-1H-imidazoles via microwave-assisted Suzuki–Miyaura cross-coupling reaction

A simple and rapid access to a variety of 4(5)-arylated imidazoles via palladium-catalyzed Suzuki–Miyaura cross-coupling reaction is described. Coupling parameters were screened for efficient C-4 arylation of N-unprotected 4-iodoimidazole with a broad range of boronic acids under microwave irradiation. Twenty-one imidazole derivatives were synthesized in modest to excellent yields in short reaction times.

Suzuki-Miyaura cross-coupling reactions of unprotected haloimidazoles.

An efficient protocol for the palladium-catalyzed Suzuki-Miyaura cross-coupling reaction of unprotected haloimidazoles is reported. The relatively mild reaction conditions allow for ready access to a wide array of functionalized imidazole derivatives in good to excellent yields. The synthetic utility of this method is demonstrated by the total synthesis of nortopsentin D.

The synthesis, photophysical and electrochemical studies of symmetrical phthalocyanines linked thiophene substituents

Tetrakis 4-(3-thienyl) and tetrakis 4-(5′-hexyl-2,2′-bithiophene) peripherally substituted zinc phthalocyanines were synthesized by using phthalonitrile derivatives. The phthalonitrile compounds were obtained through palladium catalyzed Suzuki–Miyaura cross-coupling reaction. The synthesized phthalocyanines were characterized by FT-IR, 1H NMR and MALDI-TOF-MS methods. The absorption and emission properties were studied by using UV–Vis absorption and photoluminescence spectroscopies. The electrochemical behaviors of compounds were also investigated using cyclic voltammetry (CV) measurements. The 5′-hexyl-2,2′-bithiophene substituent shifted the absorption band to red region and decreased the HOMO–LUMO energy gap of phthalocyanines.

One-Pot Cross-Coupling of Diborylmethane for the Synthesis of Dithienyl­methane Derivatives

The one-pot palladium-catalyzed Suzuki–Miyaura cross-coupling reaction of a diborylmethane with bromothiophene derivatives realized the synthesis of various dithienylmethane derivatives. Cyclopentadithiophenes, which are promising compounds in material science, can be obtained in good yields. The in situ generation of an unstable thienylmethylboronate is a key step for the present reaction.

Design, synthesis and biological evaluation of novel 4-alkapolyenylpyrrolo[1,2-a]quinoxalines as antileishmanial agents – Part III

A series of new 4-alkapolyenylpyrrolo[1,2-a]quinoxaline derivatives, original and structural analogues of alkaloid chimanine B and of previously described 4-alkenylpyrrolo[1,2-a]quinoxalines, was synthesized in good yields using efficient palladium-catalyzed Suzuki–Miyaura cross-coupling reactions. These new compounds were tested for in vitro antiparasitic activity upon three Leishmania spp. strains. Biological results showed activity against the promastigote forms of L. major, L. mexicana and L. donovani with IC50 ranging from 1.2 to 14.7 μM. In attempting to investigate if our pyrrolo[1,2-a]quinoxaline derivatives are broad-spectrum antiprotozoal compounds activities toward one Trypanosoma brucei brucei strain and the W2 and 3D7 Plasmodium falciparum strains were also investigated. In parallel, the in vitro cytotoxicity of these molecules was assessed on the murine J774 and human HepG2 cell lines. Structure–activity relationships of these new synthetic compounds are here discussed.

O-Aryloxime ether analogues as novel and efficient ligands for palladium-catalyzed Suzuki–Miyaura coupling in water

O-Aryloxime ether analogues L1–L3 were studied as ligands in palladium-catalyzed Suzuki–Miyaura cross-coupling reaction of aryl bromides and aryl boronic acids in water at room temperature. Reaction conditions for the cross-coupling were optimized using PdCl2 and Pd(OAc)2 under aerobic condition. From the three electronically diverse O-aryloxime ether ligands studied herein, the use of 1-phenyl-ethanone O-(4-chloro-phenyl)-oximeL2 exhibits the best catalytic system in the presence of K2CO3 as the base and TBAB as the promoter.

ChemInform Abstract: Tetrabutylammonium 2‐Pyridyltriolborate Salts for Suzuki—Miyaura Cross‐Coupling Reactions with Aryl Chlorides.

Palladium-catalyzed Suzuki–Miyaura cross-coupling reactions of tetrabutylammonium 2-pyridyltriolborate salts with various aryl (heteroaryl) chlorides can produce the corresponding desired coupling products with good to excellent yields. These tetrabutylammonium salts are more reactive than the corresponding lithium salts. The coupling reactions with aryl chlorides progressed in the presence of PdCl2dcpp (3 mol %) and CuI/MeNHCH2CH2OH (20 mol %) in anhydrous DMF without bases.

Carbohydrate-based phosphines as supporting ligand for palladium-catalyzed Suzuki–Miyaura cross-coupling reaction

Carbohydrate-based mono-phosphines (1 and 2) derived from glucose have been explored as supporting ligand for palladium-catalyzed Suzuki–Miyaura reaction. The combination of phosphine to palladium in a ratio of 2:1 resulted in a longer-living system than that in a ratio of 1:1. Using K2CO3 as base, aryl bromides as well as active aryl chlorides can be coupled nearly quantitatively by 0.1–0.2mol% of 1/Pd(OAc)2 with 95–99% of isolated yields. The amount of the catalyst could be lowered to 0.01mol% under the optimized condition with 80% yield at room temperature. The carbohydrate hydroxyl group in 1 was found to contribute to catalytic activity.

Palladium catalyzed novel monoarylation and symmetrical/unsymmetrical diarylation of imidazo[1,2-a]pyrazines and their in vitro anticancer activities

Palladium catalyzed Suzuki–Miyaura cross-coupling reactions are reported for the synthesis of monoarylated (at the C8 position) and symmetrical diarylated (at the C6 and C8 positions) imidazo[1,2-a]pyrazines. Monoarylated products have also been used to synthesize unsymmetrical C6/C8 diarylated products. These compounds were screened for in vitro antitumor activities against a preliminary tumor cell line panel assay.

ChemInform Abstract: Pd‐Catalyzed Suzuki—Miyaura Cross‐Coupling Reactions Between Sulfamates and Potassium Boc‐Protected Aminomethyltrifluoroborates.

AbstractThe amount of base is not general and has to be optimized for each case.

Tetrabutylammonium 2-Pyridyltriolborate Salts for Suzuki–Miyaura Cross-Coupling Reactions with Aryl Chlorides

Palladium-catalyzed Suzuki-Miyaura cross-coupling reactions of tetrabutylammonium 2-pyridyltriolborate salts with various aryl (heteroaryl) chlorides can produce the corresponding desired coupling products with good to excellent yields. These tetrabutylammonium salts are more reactive than the corresponding lithium salts. The coupling reactions with aryl chlorides progressed in the presence of PdCl2dcpp (3 mol %) and CuI/MeNHCH2CH2OH (20 mol %) in anhydrous DMF without bases.