Photolysis of S,C-sulfonium ylides derived from thioanisol, thiophene, benzothiophene, or dibenzothiophene provides products deriving from dicarbomethoxycarbene. In methanol, no rearrangement of the carbene to the ketene derivative is observed. Formation of dibenzothiophene and benzothiophene is quantitative. For the thiophene-based ylide, insertion of the carbene into the alpha-CH bond of thio...

Carbene-catalyzed reaction of carboxylic esters has the potential to offer effective synthetic solutions that cannot be readily achieved by using the more conventional aldehyde-type substrates. Here we report the first carbene-catalyzed dynamic kinetic resolution of α,α-disubstituted carboxylic esters with up to 99:1 er and 99% yield. The present study clearly illustrates the unique power of ca...

In the presence of carbon monoxide, ruthenium carbenes give a net insertion/ring expansion (Buchner reaction) into one of the aromatic rings of the N-heterocyclic carbene ligand. In alkene metathesis applications, the N-heterocyclic carbene ligand is both robust and typically inert to reactions with the metal-bound carbene. This unique reaction is completely regioselective. The complexes obtain...

In this paper are reported the results of a comprehensive mechanistic study of nucleophilic attack by amines on coordinated isocyanides in square—planar Pd(II) complexes, leading to amino—carbene complexes. The reactivity pattern that has emerged displays several facets: (i) whatever the details, in this stepwise mechanism the most prominent step always involves direct attack of the amine nitro...

Metal carbene complexes have been at the forefront of organic and organometallic synthesis and are instrumental in guiding future sustainable chemistry efforts. While classical Fischer and Schrock type carbenes have been intensely studied, compounds that do not fall within one of these categories have attracted attention only recently. In addition, applications of carbene complexes rarely take ...

A study of the reactions of ferroporphyrins, in the presence of an excess of a reducing agent, with various polyhalogenated compounds, has led to a general method of preparation of iron-carbene complexes, Fe(porphyrin) (CRR') . It has thus been possible to obtain iron complexes of the dihalogenocarbenes CC12, CBr2, CF2, CFBr and CFC1, which are thermally stable (up to 100°C) and not dissociated...

New cyclic aromatic carbene ligands bearing remote amino groups were developed. The oxidative addition of Pd(0) into the chloride precursors yielded the corresponding Pd(II) complexes whose carbene ligand was demonstrated to have stronger donor ability than classical NHCs.

The synthesis and characterization of tris(N-heterocyclic carbene)s with D(3h)-symmetry is reported; these tritopic molecules feature three independent carbene moieties that are geometrically isolated to prevent chelation.

The first examples of abnormal coordination of Ardeungo's carbene, 1,3-bis-adamantylimidazol-2-ylidene, have been isolated and structurally characterised following reaction of the free carbene with the trinuclear clusters M(3)(CO)(12) (M = Ru, Os).

Insights into the mechanism of the unusual trans-hydrogenation of internal alkynes catalyzed by {Cp*Ru} complexes were gained by para-hydrogen (p-H2 ) induced polarization (PHIP) transfer NMR spectroscopy. It was found that the productive trans-reduction competes with a pathway in which both H atoms of H2 are delivered to a single alkyne C atom of the substrate while the second alkyne C atom is...