Complexes [{Pt(C^C*)(μ-pz)}2] (HC^C*A = 1-(4-(ethoxycarbonyl)phenyl)-3-methyl-1H-imidazol-2-ylidene 1a, HC^C*B = 1-phenyl-3-methyl-1H-imidazol-2-ylidene 1b) react with methyl iodide (MeI) at room temperature in the dark to give compounds [{PtIV(C^C*)Me(μ-pz)}2(μ-I)]I (C^C*A 2a, C^C*B 2b). The reaction of 1a with benzyl bromide (BnBr) in the same co...
Methods for the Ru(dppbsa)-catalyzed hydrodeoxygenation and reductive etherification of ketones and aldehydes were developed. Carbonyl substrates without beta-CH functionality follow a hydrogenation-hydrogenolysis path, wherein the hydrogenolysis of the alkanol intermediates is the rate-limiting step. By contrast, a hydrogenation-dehydration-hydrog...
Methods for the Ru(dppbsa)-catalyzed hydrodeoxygenation and reductive etherification of ketones and aldehydes were developed. Carbonyl substrates without beta-CH functionality follow a hydrogenation-hydrogenolysis path, wherein the hydrogenolysis of the alkanol intermediates is the rate-limiting step. By contrast, a hydrogenation-dehydration-hydrog...
Binding of Lewis acidic metal ions and Br��nsted acid at the metal-oxo group of high-valent metal-oxo complexes enhances their reactivities significantly in oxidation reactions. However, such a binding of Lewis acids and proton at the metal-oxo group has been questioned in several cases and remains to be clarified. Herein, we report the synthesis, ...
The alkylation of nitroarenes with alkanols catalysed by a phosphinesulfonate chelated ruthenium complex [Ru-1] was developed. It exhibits very different reactivity and chemoselectivity depending on acidic-basic conditions. Under either neutral or acidic conditions, nitroarenes were converted to secondary and tertiary anilines, respectively, with s...
The alkylation of nitroarenes with alkanols catalysed by a phosphinesulfonate chelated ruthenium complex [Ru-1] was developed. It exhibits very different reactivity and chemoselectivity depending on acidic-basic conditions. Under either neutral or acidic conditions, nitroarenes were converted to secondary and tertiary anilines, respectively, with s...
Enantioselective reduction of ketimines was demonstrated using chiral N-heterocyclic carbene (NHC)-stabilised borenium ions in frustrated Lewis pair catalysis. High levels of enantioselectivity were achieved for substrates featuring secondary N-alkyl substituents. Comparative reactivity and mechanistic studies identify key determinants required to ...
High-valent iron-oxo species are known for their very high reactivity, and this aspect has been studied in detail over the years. The role of axial ligands in fine-tuning the reactivity of the iron(IV)-oxo species has been particularly well studied. The corresponding role of equatorial ligands, however, has rarely been explored, and is of prime imp...
Metal-exchanged zeolites are a class of heterogeneous catalysts that perform important functions ranging from selective hydrocarbon oxidation to remediation of NO x pollutants. Among these, copper and iron zeolites are remarkably reactive, hydroxylating methane and benzene selectively at low temperature to form methanol and phenol, respectively. In...
Published in Journal of the American Chemical Society
By grafting TaMe5 on Aerosil700, a stable, well-defined, silica-supported tetramethyl tantalum(V) complex, [(≡SiO)TaMe4], is obtained on the silica surface. After thermal treatment at 150 °C, the complex is transformed into two surface tantalum methylidenes, [(≡SiO)2Ta(═CH2)Me] and [(≡SiO)Ta(═CH2)Me2], which are active in alkane metathesis and comp...
