Jean-Yves Nedelec

Electrochemical cross-coupling between 2-halopyridines and aryl or heteroaryl halides catalysed by nickel-2,2′-bipyridine complexes

2-Arylpyridines can be obtained in good to high yields by electrochemical reduction using the sacrificial anode process and catalysis by nickel-2,2′-bipyridine (bpy) complexes. In a first approach functionalized arylzinc species are prepared in DMF as solvent by electrolytic reduction of the corresponding aryl-bromides or -chlorides in the presence of ZnBr2 and Ni(II)-bpy complexes and then coupled with 2-chloropyridine. In a second approach the cross-coupling occurs from the electrochemical reduction of a stoichiometric mixture of an aryl halide and 2-halopyridine in DMF in the presence of NiBr2bpy as catalyst.

Synthesis of functionalized 4-phenyl-pyridines via electrochemically prepared organozinc reagents

Abstract The efficient and convenient synthesis of various functionalized 4-phenyl-pyridines 2 is described. The key step of the procedure is the electrochemical formation of aromatic organozinc reagents 1 and their coupling with pyridinium salts. Intermediate 1,4-dihydropyridines are oxidized using mild conditions to provide functionalized 4-phenyl-pyridines in moderate to high overall yields.

Electrochemical, nickel-catalyzed Reformatsky reaction with methyl chlorodifluoroacetate

Abstract 2,2-difluoro-3-hydroxyesters are readily obtained from methyl chlorodifluoroacetate and carbonyl compounds by electrolysis in a one-compartment cell with use of a sacrificial zinc anode and a nickel-complex catalyst.

Cobalt-catalyzed electrochemical cross-coupling of functionalized phenyl halides with 4-chloroquinoline derivatives

Abstract A novel electrochemical procedure allowing the synthesis of various 4-phenylquinoline derivatives in satisfactory to high yields is described. This method relies on a cobalt-catalyzed cross-coupling reaction of functionalized phenyl halides with 4-chloroquinoline derivatives and is conducted in a one-compartment cell using the sacrificial anode process.

Cyclopropane formation by electroreductive coupling of activated olefins and gem-polyhalo compounds

Abstract Cyclopropyl derivatives have been prepared with satisfactory yields by electroreductive coupling of activated olefins and gem -polyhalo compounds. The reaction is efficient when the olefin is more easily reduced than the organic halide. Two types of intermediates can be involved to lead to the products. The radical anion of the olefin can react with the halo compound by electron-tranfer followed by radical coupling, or be reduced into the dianion which reacts by nucleophilic displacement.

An efficient inexpensive electrochemical preparation of Ruppert's reagent

Abstract The electrochemical reduction of CF 3 Br in N,N-dimethylformamide (DMF) in the presence of Me 3 SiCl and a sacrificial aluminum anode provides Me 3 SiCF 3 in ca 90 % faradaic yields.

A Novel Method of Arylation of α-Chloroketones

Abstract α-Arylated ketones were obtained in moderate to good yields by one-step electroreductive coupling of α-chloroketones and arylhalides in DMF and in the presence of a Al- or Zn-sacrificial anode and a catalytic amount of a nickel complex.

Nickel-catalyzed reductive coupling of chlorodiphenylphosphine with aryl bromides into functionalized triarylphosphines

Abstract Functionalized triarylphosphines are obtained with good yields in a one-step reaction of an equimolar mixture of chlorodiphenylphosphine and an aromatic bromide in NMP or DMF at 110°C in the presence of zinc dust and a catalytic amount of NiBr 2 (bpy). A possible catalytic pathway is discussed.

Electroreductive polymerisation of 3-substituted 2,5-dihalothiophenes: direct electrosynthesis vs. stepwise procedure involving thienylzinc intermediates

This work deals with the preparation of 3-substituted polythiophenes from the corresponding 3-substituted 2,5-dihalothiophenes, either in one electrochemical step or in two steps involving electrogenerated thienylzinc intermediates. The mild conditions used all along these electrochemical procedures allow the preparation of polythiophenes functionalised by a variety of groups in the 3 position. Poly(3-hexylthiophene) prepared in two steps shows a high proportion of regioregular HT-HT linkages (HTu2006=u2006head-to-tail). Most polymers exhibit p-doping processes in cyclic voltammetry. n-Doping processes are also observed for polythiophenes substituted either by alkyl groups or by electron-withdrawing groups.

Stereoselectivity in the Electroreductive Syntheses with Aryl and Alkenyl Halides Catalyzed by Nickel Complexes

The nickel-catalyzed electroreductive coupling between aryl halides and 2-chloropropionic acid derivatives bearing chiral auxiliaries leads to chiral 2-arylpropionic acids with high enantiomeric excesses. The electrochemical alkenylation of activated olefins catalyzed by nickel complexes occurs with complete transfer of the streochemistry of the starting alkenyl halide onto the product.