μ3-Carbonato-κ3 O:O′:O′′-tris­{(η6-ben­zene)[(R)-1-(1-amino­ethyl)naphthyl-κ2 C 2,N]ruthenium(II)} hexa­fluorido­phosphate dichloro­methane solvate

The title compound, [Ru3(C12H12N)3(CO3)(C6H6)3]PF6·CH2Cl2, was obtained unintentionally as the product of an attempted deprotonation of the monomeric parent ruthenium complex [Ru(C12H12N)(C6H6)(C2H3N)]PF6. The carbonate ligand bridges three half-sandwich cyclo­ruthenated fragments, each of them exhibiting a pseudo-tetra­hedral geometry. The configuration of the Ru atoms is S. The naphthyl groups of the enanti­opure cyclo­ruthenated benzylic amine ligands point in the same direction, adopting a propeller shape

Efficient and selective N-alkylation of amines with alcohols catalysed by manganese pincer complexes

Borrowing hydrogen (or hydrogen autotransfer) reactions represent straightforward and sustainable C-N bond-forming processes. In general, precious metal-based catalysts are employed for this effective transformation. In recent years, the use of earth abundant and cheap non-noble metal catalysts for this process attracted considerable attention in the scientific community. Here we show that the selective N-alkylation of amines with alcohols can be catalysed by defined PNP manganese pincer complexes. A variety of substituted anilines are monoalkylated with different (hetero)aromatic and aliphatic alcohols even in the presence of other sensitive reducible functional groups. As a special highlight, we report the chemoselective monomethylation of primary amines using methanol under mild conditions

Cycloruthenated complexes : from complexes to enantioselective catalysts

La cyclométallation d'amines benzyliques primaires et secondaires, chirales et achirales par [( 6-C6H6)RuCl2]2 dans l'acétonitrile a été réalisée. Les complexes cationiques correspondant, avec le groupement phényle orthométallé, sont obtenus avec de bonsThe cyclometalation of chiral and achiral primary and secondary amines occurred readily with [( 6-C6H6)RuCl2]2 in acetonitrile. Good yields of the expected cationic products in which the phenyl group was ortho metalated were obtained. Benzylamine, (R)-1

Cycloruthenated complexes : from complexes to enantioselective catalysts

La cyclométallation d'amines benzyliques primaires et secondaires, chirales et achirales par [( 6-C6H6)RuCl2]2 dans l'acétonitrile a été réalisée. Les complexes cationiques correspondant, avec le groupement phényle orthométallé, sont obtenus avec de bons rendements. La métallation des ligands benzylamine, (R)-1-phényléthylamine, (R)-1-phénylpropylamine, (R)-1-(1-naphthyl)éthylamine, (R)-1-aminotétraline, bis(R)-phényléthylamine, bis-(R)-1-naphthyléthylamine and (2R,5R)-2,5-diphénylpyrrolidine conduit à la formation des complexes désirés de formule générale [( 6-benzene)Ru(N-C)NCMe]PF6, où N-C représente le ligand orthométallé. La structure trimensionelle a été déterminée en solution par RMN 2D et à l'état solide par diffraction des rayons X. La configuration S du centre métallique est généralement associée à une formation du métallacyle et réciproquement la configuration R avec la conformation . Les complexes ruthénacycliques obtenus par orthométallation d'amines primaires et secondaires énantiopures sont des catalyseurs efficaces pour la réduction des cétones par transfert d'hydrogène (TOF jusqu à 30 000 h-1, TON jusqu à 30 000). L'énantiosélectivité pour la réduction de l'acétophénone est comprise entre 38% et 89% et entre 33% et 98% pour l'isobutyrophénone. Les catalyseurs peuvent préparés in situ, ce qui permet le criblage robotisé des ligands et des substrats. Ces complexes sont aussi des catalyseurs pour la réaction de Michael. Le mécanisme de la réduction asymétrique des cétones a été réalisée. Nous avons isolé un complexe dinucléaire de ruthénium possédant un ligand hydrure pontant linéaire non supporté qui s'isomérise spontanément en un complexe -H portant une liaison Ru-H-Ru coudée. Ces composés sont des intermédiaires stabilisés de la réaction. Les espèces actives ont été observées mais n ont pu être isolées. La réaction de transfert d'hydrogène catalysée par les complexes cycloruthénés opère via un mécanisme bifonctionnel métal-ligandThe cyclometalation of chiral and achiral primary and secondary amines occurred readily with [( 6-C6H6)RuCl2]2 in acetonitrile. Good yields of the expected cationic products in which the phenyl group was ortho metalated were obtained. Benzylamine, (R)-1-phenylethylamine, (R)-1-(1-naphthyl)ethylamine, (R)-1-aminotetraline, bis(R)-phenylethylamine, bis-(R)-1-naphthylethylamine and (2R,5R)-2,5-diphenylpyrrolidine afforded the cycloruthenated products, whose general formula is [( 6-benzene)Ru(N-C)NCMe]PF6, where N-C represents the orthometalated ligands. Substitution of the acetonitrile ligand by PMe2Ph occurred readily on the ruthenium complexes. Accurate analyses of the structure of the complexes were implemented by 2D NMR in solution and by X-ray diffraction of single crystals in the solid state. The S configuration at the metal was usually associated with a conformation of the metallacycle, and conversely, the R configuration with the conformation. Ruthenacycles obtained by cyclometalation of enantiopure aromatic primary or secondary amines are efficient catalysts for asymmetric transfer hydrogenation (TOF up to 30 000 h 1, TON up to 30 000). Enantioselectivities in the transfer hydrogenation of acetophenone ranged from 38% to 89% and from 33% to 98% for isobutyrophenone. It is possible to prepare the catalysts in situ, which allows the use of high-throughput experimentation. These complexes are also catalysts for Michael addition of aza- and carbonucleophiles upon prochiral enones. A mechanistic study of the asymmetric reduction of ketones was performed. We have isolated a dinuclear complex of ruthenium with an unsupported linear bridging hydride ligand which spontaneously isomerizes in a stable -H complex bearing a bent Ru-H-Ru bond. These compounds are stabilized intermediates of the reaction. Actives species were observed, but not isolated. The transfer hydrogenation catalyzed by cycloruthenated complexes proceeds through the metal-ligand bifunctional mechanis

Iron-Catalyzed Reduction and Hydroelementation Reactions

International audienceDuring the last two decades, iron has proved to be an interesting transition metal which is a highly valuable alternative to classical precious ones for catalyzing organic transformations including the reduction of unsaturated C–C or C–heteroatom bonds. This chapter summarizes the rapid development of iron catalyzed selective reductions of alkene, alkyne, carbonyl and carboxylic derivatives. The emerging topic of hydroboration of alkenes and alkynes is also describe

Complexes cycloruthénés (Des complexes aux catalyseurs énantiosélectifs)

La cyclométallation d amines benzyliques primaires et secondaires, chirales et achirales par [( 6-C6H6)RuCl2]2 dans l acétonitrile a été réalisée. Les complexes cationiques correspondant, avec le groupement phényle orthométallé, sont obtenus avec de bons rendements. La métallation des ligands benzylamine, (R)-1-phényléthylamine, (R)-1-phénylpropylamine, (R)-1-(1-naphthyl)éthylamine, (R)-1-aminotétraline, bis(R)-phényléthylamine, bis-(R)-1-naphthyléthylamine and (2R,5R)-2,5-diphénylpyrrolidine conduit à la formation des complexes désirés de formule générale [( 6-benzene)Ru(N-C)NCMe]PF6, où N-C représente le ligand orthométallé. La structure trimensionelle a été déterminée en solution par RMN 2D et à l état solide par diffraction des rayons X. La configuration S du centre métallique est généralement associée à une formation du métallacyle et réciproquement la configuration R avec la conformation . Les complexes ruthénacycliques obtenus par orthométallation d amines primaires et secondaires énantiopures sont des catalyseurs efficaces pour la réduction des cétones par transfert d hydrogène (TOF jusqu à 30 000 h-1, TON jusqu à 30 000). L énantiosélectivité pour la réduction de l acétophénone est comprise entre 38% et 89% et entre 33% et 98% pour l isobutyrophénone. Les catalyseurs peuvent préparés in situ, ce qui permet le criblage robotisé des ligands et des substrats. Ces complexes sont aussi des catalyseurs pour la réaction de Michael. Le mécanisme de la réduction asymétrique des cétones a été réalisée. Nous avons isolé un complexe dinucléaire de ruthénium possédant un ligand hydrure pontant linéaire non supporté qui s isomérise spontanément en un complexe -H portant une liaison Ru-H-Ru coudée. Ces composés sont des intermédiaires stabilisés de la réaction. Les espèces actives ont été observées mais n ont pu être isolées. La réaction de transfert d hydrogène catalysée par les complexes cycloruthénés opère via un mécanisme bifonctionnel métal-ligandThe cyclometalation of chiral and achiral primary and secondary amines occurred readily with [( 6-C6H6)RuCl2]2 in acetonitrile. Good yields of the expected cationic products in which the phenyl group was ortho metalated were obtained. Benzylamine, (R)-1-phenylethylamine, (R)-1-(1-naphthyl)ethylamine, (R)-1-aminotetraline, bis(R)-phenylethylamine, bis-(R)-1-naphthylethylamine and (2R,5R)-2,5-diphenylpyrrolidine afforded the cycloruthenated products, whose general formula is [( 6-benzene)Ru(N-C)NCMe]PF6, where N-C represents the orthometalated ligands. Substitution of the acetonitrile ligand by PMe2Ph occurred readily on the ruthenium complexes. Accurate analyses of the structure of the complexes were implemented by 2D NMR in solution and by X-ray diffraction of single crystals in the solid state. The S configuration at the metal was usually associated with a conformation of the metallacycle, and conversely, the R configuration with the conformation. Ruthenacycles obtained by cyclometalation of enantiopure aromatic primary or secondary amines are efficient catalysts for asymmetric transfer hydrogenation (TOF up to 30 000 h 1, TON up to 30 000). Enantioselectivities in the transfer hydrogenation of acetophenone ranged from 38% to 89% and from 33% to 98% for isobutyrophenone. It is possible to prepare the catalysts in situ, which allows the use of high-throughput experimentation. These complexes are also catalysts for Michael addition of aza- and carbonucleophiles upon prochiral enones. A mechanistic study of the asymmetric reduction of ketones was performed. We have isolated a dinuclear complex of ruthenium with an unsupported linear bridging hydride ligand which spontaneously isomerizes in a stable -H complex bearing a bent Ru-H-Ru bond. These compounds are stabilized intermediates of the reaction. Actives species were observed, but not isolated. The transfer hydrogenation catalyzed by cycloruthenated complexes proceeds through the metal-ligand bifunctional mechanism.STRASBOURG-Sc. et Techniques (674822102) / SudocSudocFranceF

Homogeneous iron catalysis – Highlights on the increasing impact of a non-noble metal

International audienc

A convenient nickel-catalysed hydrosilylation of carbonyl derivatives.

International audienceHydrosilylation of aldehydes and ketones catalysed by nickel acetate and tricyclohexylphosphine as the catalytic system was demonstrated using polymethylhydrosiloxane as a cheap reducing reagent

Methylation of secondary amines with dialkyl carbonates and hydrosilanes catalysed by iron complexes.

International audienceMethylation of secondary amines was achieved using dimethyl carbonate or diethyl carbonate as the C1 source under the catalysis of well-defined half-sandwich iron complexes bearing an N-heterocyclic carbene ligand. The reaction proceeded under mild conditions in the presence of hydrosilanes as the reductants, and the amines were obtained with good to excellent isolated yields

Unexpected selectivity in ruthenium-catalyzed hydrosilylation of primary amides: synthesis of secondary amines.

International audienceSelective ruthenium-catalyzed reductive coupling of primary amides under hydrosilylation conditions is achieved using an one pot procedure. Using 3 equiv. of phenylsilane and [RuCl2(mesitylene)]2 (1-2 mol%) as the catalyst at 100 °C under neat conditions, secondary symmetric amines were obtained in good yields and with high chemoselectivities