Efficient metal-free hydrosilylation of tertiary, secondary and primary amides to amines

International audienceHydrosilylation of secondary and tertiary amides to amines is described using catalytic amounts of B(C6F5)3. The organic catalyst enables the reduction of amides with cost-efficient, non-toxic and air stable PMHS and TMDS hydrosilanes. The methodology was successfully extended to the more challenging reduction of primary amides

Iron-catalyzed hydrosilylation of CO2: CO2 conversion to formamides and methylamines

International audienceno abstrac

Understanding the catalytic carbonylation of epoxides for the valorization of carbon monoxide

International audienceSmall molecules released as gaseous wastes by the industries, such as CO and CO2, are attractive C1 building blocks for the production of chemicals. They can indeed reduce our dependence on fossil feedstocks. The catalytic insertion of carbon dioxide into epoxides has been developed over the last decades for the production of cyclic and polymeric carbonates, with industrial success. The same strategy can be used for the production of polyester from epoxides and carbon monoxide, possibly released from the production of steel. The catalytic carbonylation of epoxides with gaseous CO leads to $\beta$-lactones and this reaction has attracted a particular attention over the past few years. Yet, only few catalytic systems have been developed, all containing a cobalt carbonyl complex assisted by a Lewis acid. Herein, we disclose a theoretical study to understand the mechanism6 of carbonylation of epoxides using a cobalt catalyst with Lewis acids. The influence of the Lewis acidy on the activity was investigated through various boron compounds. The DFT calculations, linked with a Lewis acidity scale, can thus be used as a guide for the development of a novel catalytic system

Catalytic hydrosilylation of oxalic acid: chemoselective formation of functionalizedC2-products

International audienceOxalic acid is an attractive entry to functionalized C2-products because it can be formed by C–C coupling of two CO2 molecules under electrocatalytic reduction. Herein, we describe the first attempts to reduce oxalic acid by catalytic hydrosilylation. Using B(C6F5)3 as a Lewis acidic catalyst, oxalic acid can be converted to reduced C2-molecules, with high chemoselectivity, under mild reaction conditions

Reductive functionalization of CO2 with amines: an entry to formamide, formamidine and methylamine derivatives

International audienceCO2 utilization for the production of C1-containing molecules is a desirable route to value-added chemicals. In this perspective, we summarize the recent results devoted to the formation of nitrogen compounds obtained by reductive functionalization of CO2 in the presence of amines. Using mild reductants, such as molecular hydrogen, hydrosilanes and hydroboranes, novel catalytic reactions have been designed in the last few years to facilitate the reductive functionalization of CO2 to formamide, formamidine and methylamine derivatives. While early efforts were devoted to the formylation of N-H bonds, efficient organic and metal catalysts have been developed lately to promote the complete deoxygenation of CO2 to benzimidazoles, quinazolinones, formamidines and methylamines. Finally, the opportunities and challenges facing the practical use of CO2 in the production of nitrogen-containing molecules are discussed

Formic acid disproportionation to methanol and CO2_2 reduction

International audienc

Catalytic methylation of aromatic amines with formic acid as the unique carbon and hydrogen source

International audienceA novel methodology is presented for the direct methylation of amines, using formic acid as a unique source of carbon and hydrogen. Based on ruthenium(II) catalysts, the formation of the N-CH3 group proceeds via an efficient formylation/transfer hydrogenation pathwa

Nitrite complexes of the rare earth elements

International audienceThe coordination chemistry of the nitrite anion has been investigated with rare earth elements, and the resulting complexes were structurally characterized. Among them, the first homoleptic examples of nitrite complexes of samarium, ytterbium and yttrium are described. The coordination behavior of the nitrite ion is directly controlled by the ionic radius of the metal cation. While the nitrito ligand is stable in the coordination sphere of cerium(III), it is readily reduced by SmI2

Synergistic effects in ambiphilic phosphino-borane catalysts for the hydroboration of CO2_2

International audienceThe benefit of combining both a Lewis acid and a Lewis base in a catalytic system has been established for the hydroboration ofCO$_2$, using ferrocene-based phosphine, borane and phosphino-borane derivative

Convergent Reductive Depolymerization of Wood Lignin to Isolated Phenol Derivatives by Metal-Free Catalytic Hydrosilylation

International audienceThe first examples of reductive depolymerization of lignin are reported under metal-free conditions. Using hydrosilanes as reductants and B(C6F5)3 as a Lewis acid catalyst, wood lignin is efficiently converted to a narrow distribution of phenol derivatives at room temperature. A three-step methodology based on the selection of the wood species and the lignin extraction method followed by a convergent reductive depolymerization enables the production of four structurally defined aromatic compounds. The phenol products were successfully isolated in 7–24 wt% yield from lignin and 0.5–2.4 wt% yield from wood. The strategy is found to be robust and is applied to 15 different wood plants, including gymnosperm and angiosperm species. The efficiency of this novel methodology has been evaluated based on spectroscopic characterization of the lignin preparations and isolated yields of mono-aromatic products