Aryl Coupling Reactions Research Articles

Enantioselective construction of biaryl part in the synthesis of stegane related compounds

A Pd-mediated intramolecular aryl–aryl coupling reaction of phenyl benzoate derivatives were examined to form benzo[ c]chromen-6-ones, and then enantioselective lactone-opening reaction with a borane–oxazaborolidine combination was carried out. The resulting biphenyl was transformed into a key intermediate for the stegane related compounds. The absolute configuration of the biphenyl is also discussed.

Flexible N,N,N-chelates as supports for iron and cobalt chloride complexes; synthesis, structures, DFT calculations and ethylene oligomerisation studies.

The aryl-substituted N-picolylethylenediamine and diethylenetriamine ligands, (ArNHCH(2)CH(2))[(2-C(5)H(4)N)CH(2)]NH and (ArNHCH(2)CH(2))(2)NH (Ar = 2,6-Me(2)C(6)H(3), 2,4,6-Me(3)C(6)H(2)), have been prepared by employing palladium-catalysed N-C(aryl) coupling reactions of the corresponding primary amines with aryl bromide. Treatment of MCl(2) with (ArNHCH(2)CH(2))[(2-C(5)H(4)N)CH(2)]NH affords [[(ArNHCH(2)CH(2))((2-C(5)H(4)N)CH(2))NH]CoCl(2)](Ar = 2,6-Me(2)C(6)H(3) 1a; 2,4,6-Me(3)C(6)H(2)) 1b and [[(ArNHCH(2)CH(2))((2-C(5)H(4)N)CH(2))NH]FeCl(2)](n)(n= 1, Ar = 2,6-Me(2)C(6)H(3) 2a; n= 2, 2,4,6-Me(3)C(6)H(2) 2b) in high yield. The X-ray structures of 1a and 1b are isostructural and reveal the metal centres to adopt distorted trigonal bipyramidal geometries with the N,N,N-chelates adopting fac-structures. A facial coordination mode of the ligand is also observed in bimetallic 2b, however, in 2a the N,N,N-chelate adopts a mer-configuration with the metal centre adopting a geometry best described as square pyramidal. Solution studies indicate that mer-fac isomerisation is a facile process for these systems at room temperature. Quantum mechanical calculations (DFT) have been performed on 1a and 2a, in which the ligands employed are identical, and show the fac- to be marginally more stable than the mer-configuration for cobalt (1a) while for iron (2a) the converse is evident. Reaction of (ArNHCH(2)CH(2))(2)NH with CoCl(2) gave the five-coordinate complexes [[(ArNHCH(2)CH(2))(2)NH]CoCl(2)](Ar = 2,6-Me(2)C(6)H(3) 3a, 2,4,6-Me(3)C(6)H(2) 3b), in which the ligand adopts a mer-configuration; no reaction occurred with FeCl(2). All complexes 1-3 act as modest ethylene oligomerisation catalysts on activation with excess methylaluminoxane (MAO); the iron systems giving linear alpha-olefins while the cobalt systems give mixtures of linear and branched products.

Nickel-Catalyzed Electrochemical Coupling of Aryl, Heteroaryl or Vinyl Halides with Activated Alkyl Chlorides: Synthetic and Stereochemical Aspects

We report coupling reactions of aryl, heteroaryl or vinyl halides with activated alkyl halides, using nickel catalysis combined with an electrochemical process. Synthetic and stereochemical aspects are presented. This minireview highlights electrosynthesis in the field of synthesis and catalysis.

Ligand‐Free Palladium Catalysis of Aryl Coupling Reactions Facilitated by Grinding.

AbstractFor Abstract see ChemInform Abstract in Full Text.

The O‐Substitution Pattern of the MoCl5‐Mediated Oxidative Aryl—Aryl Coupling Reaction.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Aryl—Aryl Coupling Reaction Catalyzed by a Palladium Reagent Prepared from Pd(OAc)2 and n‐Bu3P.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Ruthenium(III) Schiff Base Complexes: Catalytic Activity in Aryl–Aryl Coupling Reaction and Antimicrobial Activity

The synthesis and characterization of several hexa‐coordinated ruthenium(III) Schiff base complexes of the type [RuX(EPh3)2(L)] (E=P or As; X=Cl or Br; L = anion of the Schiff bases derived by the condensation of salicylaldehyde or o‐hydroxyacetophenone with benzoylhydrazine or p‐chlorobenzoylhydrazine) are reported. IR, EPR, electronic spectra and cyclic voltammetric data of the complexes are discussed. An octahedral geometry has been tentatively proposed for all of these complexes. The new complexes have been subjected to a catalytic activity study in the aryl–aryl coupling reaction and also to an antibacterial study.

Ligand-free palladium catalysis of aryl coupling reactions facilitated by grinding

Ligand-free palladium-catalysed Suzuki coupling reactions and homo-couplings of boronic acids have been facilitated by grinding. The reactions are rapid (10–30 min) and can be performed without the need to exclude air and moisture.

Patents on tetracycline and tetracycline derivatives as antimicrobials: January 1998 ? October 2002

This review summarises patents claiming novel tetracyclines specified for antibacterial or antimicrobial use published from January 1998 to October 2002. A brief overview of the mode of action and important resistance mechanisms of the tetracycline class is presented. All of the novel tetracyclines cited were prepared through application of known chemistry to a small number of core tetracyclines with major focus upon the aromatic ring positions C-7, C-8 and C9; metal-catalysed aryl coupling reactions such as the Suzuki, Stille and Heck couplings were cited in numerous examples. Core tetracyclines used to derive novel chemical matter include tetracycline, doxycycline, sancycline and minocycline, among others, and the chemistry is claimed for alternative tetracycline templates. Novel tetracyclines were claimed for use against Gram-negative and Gram-positive bacteria including strains exhibiting tetracycline-specific efflux and ribosomal protection resistance. Tetracyclines were also claimed for use against cryptosporidium and as antifungal agents. In all cases, limited detailed information on biological profiles was cited.

A new, highly fluorescent terpyridine which responds to zinc ions with a large red-shift in emission.

A sequence of three metal-catalysed aryl coupling reactions leads to the new ligand 4'-(4-N,N-diphenylaminophenyl)-2,2':6',2"-terpyridine, the intense ICT emission of which undergoes a large red-shift upon binding of zinc ions, providing a unique response over other common metal ions.

The Aryl—Aryl Coupling Reaction of 1‐Naphthol with SnCl4 for 2,2′‐Binaphthol Synthesis and Its Application to the Biomimetic Synthesis of Binaphthoquinone Isolated from Plumbago zeylanica.

AbstractFor Abstract see ChemInform Abstract in Full Text.

ChemInform Abstract: Novel Concepts in Directed Biaryl Synthesis. Part 88. Oxidative Aryl Coupling Reactions: A Biomimetic Approach to Configurationally Unstable or Axially Chiral Biaryl Natural Products and Related Bioactive Compounds.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The aryl–aryl coupling reaction of 1-naphthol with SnCl4 for 2,2′-binaphthol synthesis and its application to the biomimetic synthesis of binaphthoquinone isolated from Plumbagozeylanica

A simple method for the direct synthesis of 2,2′-binaphthols was developed, utilizing aryl–aryl coupling reaction via electron donor–acceptor complexes of 1-naphthols with SnCl4. Heating of the complex in a sealed tube afforded the corresponding o-o coupling product in excellent yield. This method was utilized for a biomimetic synthesis of the binaphthoquinone, 3,3′-biplumbagin, isolated from Plumbago zeylanica.

Chemistry of 1,2-allenyl/propargyl metal species. A personal account

Abstract The Pd (0) -catalyzed coupling reaction of aryl and electron-deficient alkenyl halides with the organozinc reagents formed by the subsequent treatment of 1-phenylalk-1-ynes with n-BuLi and ZnBr2 with or without a catalytic amount of HgCl2 was studied. Both the allene-formation- and the alkyne-formation-type coupling reactions were observed, depending on the structures of organic halides and 1-arylalk-1-ynes.

Oxidative aryl coupling reactions: a biomimetic approach to configurationally unstable or axially chiral biaryl natural products and related bioactive compounds

Phenolic and non-phenolic oxidative aryl coupling reactions were successfully used in the efficient synthesis of diverse natural products and related compounds in the fields of biphenyls, biscarbazoles and bisnaphthylisoquinolines. For sterically more hindered biaryls, which consequently show the phenomenon of axial chirality, the products were prepared in an atropisomerically pure form. Their absolute axial configurations were assigned mainly by experimental and computational CD investigations.

Synthesis of trisphaeridine and norchelerythrine through palladium-catalyzed aryl–aryl coupling reaction

Total syntheses of trisphaeridine (3) and norchelerythrine (4), fully aromatized phenanthridine and benzo[c]phenanthridine alkaloids, were accomplished via the internal aryl–aryl coupling reaction of halo amides protected by a methoxymethyl group with the palladium reagent, followed by reduction with lithium aluminium hydride and treatment with hydrochloric acid.

A new vinyl ether type linker for solid-phase synthesis

A new vinyl ether type of linker based on 4-hydroxy phenethyl alcohol is developed for the solid-phase synthesis as demonstrated in the Suzuki type of aryl–aryl coupling reaction for the preparation of various biphenyl tetrazole derivatives.

Cycloruthenated tertiary amines and ethylene: further insight to the Ru-mediated olefin–aryl coupling reaction

The reaction between cycloruthenated N,N-dimethylbenzylamine and ethylene under very mild conditions afforded 2-vinyl-N,N-dimethylbenzylamine and an organometallic Ru derivative resulting from the overall insertion of one carbon atom in the Ru–C bond of the starting material.

ChemInform Abstract: The Use of Ni(CO)2(PPh3)2 in Aryl and Pyridyl Coupling Reactions.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Combining N-heterocyclic carbenes and phosphines: improved palladium(II) catalysts for aryl coupling reactions

Complexes of the type (NHC)Pd(PR 3)I 2 with bulky N-heterocyclic carbenes (NHC) are efficient catalysts for aryl coupling reactions such as the Suzuki and Stille cross-coupling reaction. These catalysts combine the advantageous stability of bis(carbene) complexes and the good activity of the bis(phosphine) complexes in these reactions. Both arylbromides and arylchlorides can be used as substrates.