Sylvie Condon

Nickel‐Catalyzed Electrochemical Arylation of Activated Olefins

Nickel-catalyzed electrochemical conjugate additions of substituted aryl bromides to activated olefins under recently optimized reaction conditions are reported. Good to high yields were obtained, whatever the nature of substituents in the meta- and para-positions of the benzene ring. In the ortho-substituted series, yields were good with electron-donating substituents, but low with electron-withdrawing groups. The activation of aryl chlorides and the sequential functionalization of aryl dihalides were also investigated.

An Electrochemical Nickel-Catalyzed Arylation of 3-Amino-6-Chloropyridazines

3-Amino-6-aryl- and 3-amino-6-heteroarylpyridazines have been obtained in generally good yield using a nickel-catalyzed electrochemical cross-coupling between 3-amino-6-chloropyridazines and aryl or heteroaryl halides at room temperature. Comparative experiments involving classical palladium-catalyzed reactions, such as Suzuki, Stille, or Negishi cross-couplings, reveal that the electrochemical method can constitute a reliable alternative tool for biaryl formation. A possible reaction mechanism is proposed on the basis of electrochemical analyses.

Catalysis by nickel-2,2′-dipyridylamine complexes of the electroreductive coupling of aromatic halides in ethanol

Abstract Nickel-2,2′-dipyridylamine complexes are efficient catalysts for achieving in pure ethanol electroreductive dimerisation of aromatic halides or arylation of activated olefins.

Preparation and Synthetic Applications of Trivalent Arylbismuth Compounds as Arylating Reagents. A Review

Introduction ................................................................................... 90 I. Preparation of Trisarylbismuth Compounds ................................... 91 1.1. Preparation of Homo Trisarylbismuth Compounds...................................91 1.2. Preparation of Mixed Trisarylbismuth Compounds ..................................98 1.3. Preparation of Chiral Trisarylbismuth Compounds ................................104 II. Trisarylbismuth Compounds as Arylating Reagents in Organic Transformations ........................................................................... 106 2.1. Copper-catalyzed N–C (Aryl) Bond Formation .......................................106 2.2. Copper-catalyzed O–C (Aryl) Bond Formation .......................................111 2.3. Copper-catalyzed S–C (Aryl) Bond Formation........................................113 2.4. Palladium-catalyzed C–C (Aryl) Bond Formation...................................113 2.4.1. Cross-coupling with Aryl Halides, Aryl Triflates and Heteroaryl Halides114 2.4.2. Cross-coupling with Alkenyl Halides...................................................119 2.4.3. Cross-coupling with Acyl Chlorides ....................................................121 2.4.4. Cross-coupling with Propargylic Halides, Allylic Halides, Acetates, Carbonates and Vinyl Epoxides .......................................................123 2.4.5. Carbonylative Reactions ....................................................................125 III. Trisarylbismuth Compounds in Asymmetric Synthesis.................. 126 Conclusion.................................................................................... 127 References .................................................................................... 127

Valorization of glycerol 1,2-carbonate as a precursor for the development of new synthons in organic chemistry

Conjugate addition reactions are efficiently performed by a very simple electrochemical method using nickel complexes as catalysts. In this paper, we reported a new method for the valorization of glycerol 1,2-carbonate. Firstly, we prepared the activated glycerol 1,2-carbonate derivatives (halogen or pseudo-halide derivatives), and secondly applied these halogen derivatives in coupling reactions by electrochemical methods with organic compounds and environment-friendly solvent (propylene carbonate). To our knowledge, this is the first report of creation of carbon–carbon bonds on the glycerol 1,2-carbonate and of the synthesis of these compounds.

Electrochemical Synthesis and Characterisation of Alternating Tripyridyl-Dipyrrole Molecular Strands with Multiple Nitrogen-Based Donor-Acceptor Binding Sites

Synthesis of alternating pyridine-pyrrole molecular strands composed of two electron-rich pyrrole units (donors) sandwiched between three pyridinic cores (acceptors) is described. The envisioned strategy was a smooth electrosynthesis process involving ring contraction of corresponding tripyridyl-dipyridazine precursors. 2,6-Bis[6-(pyridazin-3-yl)]pyridine ligands 2a-c bearing pyridine residues at the terminal positions were prepared in suitable quantities by a Negishi metal cross-coupling procedure. The yields of heterocyclic coupling between 2-pyridyl zinc bromide reagents 12a-c and 2,6-bis(6-trifluoromethanesulfonylpyridazin-3-yl)pyridine increased from 68 to 95% following introduction of electron-donating methyl groups on the metallated halogenopyridine units. Favorable conditions for preparative electrochemical reduction of tripyridyl-dipyridazines 2b,c were established in THF/acetate buffer (pH 4.6)/acetonitrile to give the targeted 2,6-bis[5-(pyridin-2-yl)pyrrol-2-yl]pyridines 1b and 1c in good yields. The absorption behavior of the donor-acceptor tripyridyl-dipyrrole ligands was evaluated and compared to theoretical calculations. Highly fluorescent properties of these chromophores were found (ν(em)≈2 × 10(4) cm(-1) in MeOH and CH(2)Cl(2)), and both pyrrolic ligands exhibit a remarkable quantum yield in CH(2)Cl(2) (φ(f)=0.10). Structural studies in the solid state established the preferred cis conformation of the dipyrrolic ligands, which adopting a planar arrangement with an embedded molecule of water having a complexation energy exceeding 10 kcal mol(-1). The ability of the tripyridyl-dipyrrole to complex two copper(II) ions in a pentacoordinate square was investigated.

ELECTROSYNTHESIS OF NEW FUNCTIONALIZED DIFLUORO ALLYLSILANES

Abstract An efficient electrochemical silylation of chlorodifluoromethyl enol ethers 2 afforded in good yields the new functionalized difluoromethyl allylsilanes 1 on a preparative scale. These silanes reacted as difluoromethyl anion equivalents with an aldehyde as electrophile, providing functionalized α-difluoromethyl alcohols 4 .

First principle investigations of organobismuth palladium-catalyzed C–C coupling reaction: mechanism, chemoselectivity and solvent effects

A first principle study of the cross-coupling reaction between 3-chloro-6-iodopyridazine and triphenylbismuth under palladium catalysis has been carried out. The approach selected for this investigation is the density functional theory within the framework of the PBE0 and B3LYP hybrid exchange–correlation functionals, with and without including empirical corrections for the dispersion forces at the GD3 level. For this reaction, a three-step mechanism including an oxidative addition, a transmetalation and a reductive elimination has been proposed. All intermediates and transition states have been fully characterized. The energy profile is deduced in gas phase and in solvent. Calculations suggest that the oxidative addition is the rate-determining step for the entire cross-coupling reaction.