First-row metal complexes often undergo undesirable one-electron redox processes during two-electron steps of catalytic cycles. We report the amination of aryl chlorides and bromides with primary aliphatic amines catalyzed by a well-defined, single-component nickel precursor (BINAP)Ni(η(2)-NC-Ph) (BINAP = 2,2'-bis(biphenylphosphino)-1,1'-binaphthalene) that minimizes the formation of Ni(I) spec...

Activation of a strong aryl-Br bond of a halogenated vinylarene by nickel(0) is demonstrated in the presence of aryl-I containing substrates. eta2-Coordination of Ni(PEt3)2 to the C=C moiety of halogenated vinylarenes is kinetically preferable and is followed by an intramolecular aryl-halide bond activation process. This "ring-walking" process is quantitative and proceeds under mild reaction co...

A mild and general method for the conversion of aryl, heteroaryl, and vinyl bromides into the corresponding iodides was developed utilizing a catalyst system comprising 5 mol % of CuI and 10 mol % of a 1,2- or 1,3-diamine ligand. A variety of polar functional groups are tolerated, and even N-H containing substrates such as sulfonamides, amides, and indoles are compatible with the reaction condi...

Catalytic cross-coupling of aryl Grignard reagents with primary and secondary alkyl halides bearing beta-hydrogens is achieved using Fe(III) amine-bis(phenolate) halide complexes.

Palladium-catalyzed cross-coupling of phenyl, vinyl, and allyl siloxane derivatives proceeded in good to excellent yield with aryl iodides, electron-deficient aryl bromides, and allylic benzoates. Methyl and 2,2,2-trifluoroethyl siloxane derivatives can be employed in the coupling reaction. Electron-donating and -withdrawing groups are tolerated on the aryl halide without affecting the coupling...

An unreported product outcome from an intended Sonogashira coupling is presented. The generality of this finding has been demonstrated by screening of a range of pre-catalysts. Mechanistic studies are consistent with the tetra-aryl benzene product forming by interception of the aryl halide oxidative addition intermediate by repeated acetylene insertion.

The nucleophilicity of arenethiols can be augmented via hydrogen bonding with "naked" halide anion. The activity of the halide anions follow the order F(-) >> Cl(-) approximately Br(-) approximately I(-) and is dependent on the countercation (Bu(4)N approximately Cs approximately K > Na >> Li). The solvent plays an important role in nucleophilic activation as well as regeneration of the effecti...

Relatively mild and highly efficient CuI-catalyzed N-arylation procedures for nitrogen-containing heterocycles (e.g., imidazoles, benzimidazoles, pyrroles, pyrazoles, indoles, triazoles, etc.) with aryl and heteroaryl halides have been developed. The protocols can be performed easily and tolerate a number of functional groups, such as ester, nitrile, nitro, ketone, free hydroxyl, and free prima...

Direct arylation reactions of nitrobenzenes and aryl halides occur in good yield and high ortho regioselectivity. These reactions can be performed on gram scale with as few as 3 equiv of the nitro arene relative to the aryl halide. The synthetic utility of this method is demonstrated via rapid synthesis of a Boscalid intermediate.

* corresponding author, e-mail: [email protected] ; tel : (216) 74276400 ; fax : (216) 74274437 ABSTRACT: In this work, we have studied the effect of the halide nature in the coupling of styrene with halide benzene catalysed by palladium acetate or chloride. The activation by a catalyst of phase-transfer type Aliquat-336 improves the reactivity in N, N-dimethylformamide-water mixture. The...