Thierry Achard

N-Phosphino-p-tolylsulfinamide Ligands: Synthesis, Stability, and Application to the Intermolecular Pauson−Khand Reaction

Here we synthesized a family of racemic and optically pure N-phosphino-p-tolylsulfinamide (PNSO) ligands. Their stability and coordination behavior toward dicobalt-alkyne complexes was evaluated. Selectivities of up to 3:1 were achieved in the ligand exchange process with (mu-TMSC2H)Co2(CO)6. The resulting optically pure major complexes were tested in the asymmetric intermolecular Pauson-Khand reaction and yielded up to 94% ee. X-ray studies of the major complex 18a indicated that the presence of an aryl group on the sulfinamide reduces the hemilabile character of the PNSO ligands.

Enol Acetal Synthesis through Carbenoid CH Insertion into Tetrahydrofuran Catalyzed by CpRu Complexes

Intermolecular C—O instead of —CC bond formation is achieved with [CpRu(CH3CN)3][PF6] and diimine ligands as catalysts of the decomposition of α-diazo-β-ketoesters in THF leading to original products of 1,3 CH insertion.

[CpRu]-Catalyzed Carbene Insertions into Epoxides: 1,4-Dioxene Synthesis through S N 1-Like Chemistry with Retention of Configuration

Rather than lead to the usual deoxygenation pathway, metal carbenes derived from α-diazo-β-ketoesters undergo three-atom insertions into epoxides using a combination of 1,10-phenanthroline and [CpRu(CH3CN)3][BAr(F)] as the catalyst. Original 1,4-dioxene motifs are obtained as single regio- and stereoisomers. A perfect syn stereochemistry (retention, e.r. up to 97:3) is observed for the ring opening, which behaves as an S(N)1-like transformation.

Advances in Homogeneous Catalysis Using Secondary Phosphine Oxides (SPOs): Pre-ligands for Metal Complexes.

The secondary phosphine oxides are known to exist in equilibrium between the pentavalent phosphine oxides (SPO) and the trivalent phosphinous acids (PA). This equilibrium can be displaced in favour of the trivalent tautomeric form upon coordination to late transition metals. This tutorial review provides the state of the art of the use of secondary phosphine oxides as pre-ligands in transition metal-catalysed reactions. Using a combination of SPOs and several metals such as Pd, Pt, Ru, Rh and Au, a series of effective and original transformations have been obtained and will be discussed here.

Synthesis of Spiro Ketals, Orthoesters, and Orthocarbonates by CpRu-Catalyzed Decomposition of α-Diazo-β-ketoesters

Reactions of α-diazo-β-ketoesters with cyclic ketones, lactones, and carbonates are reported. Thanks to the combined use of salt [CpRu(CH3CN)3][BArF] and 1,10-phenanthroline as catalyst for the diazo decomposition, effective and practical syntheses of spiro bicyclic ketals, orthoesters, and orthocarbonates are afforded.

Optically active sum-frequency generation as an advanced tool for chiral metallopolymer material

Metallopolymers incorporating metal ions and polytopic ligands offer the advantage to be easily obtained through a self-assembly process in solution but offer great prospects in the development of multifunctional, smart, even self-healing, materials. We have found that chiral enantiopure ligands containing bis(oxazoline) units in combination with Ni(II) salts generate well-defined thin films either by drop casting or by spin-coating and we demonstrate that the condensation process of these chiral metallosupramolecular assemblies can be characterized through optically active sum-frequency generation.

Original Reactivity of α-Diazo-β- ketoesters Catalyzed by CpRu Complexes

Using α-diazo-β-ketoesters as reagents and combinations of CpRu fragments and diimine ligands as catalysts, a series of original transformations have been obtained that can be rationalized by the formation of metal carbenes and metal-bound ylide intermediates. Interesting 1,3-dioxole, enol-acetal and 1,4-dioxene motifs are obtained directly when the reactive mixture is reacted in presence of aldehydes or ketones, THF and epoxides.