84-15-1Relevant articles and documents
Comparison of the Oxidative Coupling Reactions of Benzene with Those of Methane of Rare Earth Oxide Catalysts
Sugiyama, Shigeru,Ookubo, Takashi,Shimodan, Kazuaki,Hayashi, Hiromu,Moffat, John B.
, p. 3339 - 3345 (1994)
The oxidative coupling of benzene has been compared with that of methane on La2O3, CeO2, Pr6O11, and Sm2O3. At temperatures greater than 1048 K, the gas phase oxidative coupling of benzene appears to be predominant, while the oxidation occurs catalytically at 873 K. The conversion of benzene and of methane at 873 K follows the order of Sm2O3>La2O3>Pr6O11>CeO2, suggesting that the abstraction of hydrogen from the aromatic and the saturated compounds depends primarily on the nature of the catalyst but not the reactant. Ancillary information has also been obtained from the results of XPS analyses of both fresh catalysts and those previously used in one of the reactions.
Suzuki cross-coupling of hexachlorobenzene promoted by the Buchwald ligands
Burukin, A. S.,Vasil’ev, A. A.,Zhdankina, G. M.,Zlotin, S. G.
, p. 169 - 172 (2022/02/17)
The study of cross-coupling between hexachlorobenzene and phenylboronic acid comprised five Buchwald ligands, from which 2-dicyclohexylphosphino-2′-(dimethylamino)biphenyl (DavePHOS) provided the best conversion. When excess of phenylboronic acid was used, a mixture of isomeric tri-, tetra- and pentaphenyl-substituted derivatives in the ～10:70:20 ratio was obtained, along with minor amounts of hydrodechlorination products.
Tris-NHC-propagated self-supported polymer-based Pd catalysts for heterogeneous C-H functionalization
Choudhury, Joyanta,Dutta, Tapas Kumar,Mandal, Tanmoy,Mohanty, Sunit
supporting information, p. 10182 - 10185 (2021/10/12)
Three-dimensionally propagated imidazolium-containing mesoporous coordination polymer and organic polymer-based platforms were successfully exploited to develop single-site heterogenized Pd-NHC catalysts for oxidative arene/heteroarene C-H functionalization reactions. The catalysts were efficient in directed arene halogenation, and nondirected arene and heteroarene arylation reactions. High catalytic activity, excellent heterogeneity and recyclability were offered by these systems making them promising candidates in the area of heterogeneous C-H functionalization, where efficient catalysts are still scarce.
Experimental and Computational Studies towards Chemoselective C?F over C?Cl Functionalisation: Reversible Oxidative Addition is the Key
Jacobs, Emily,Keaveney, Sinead T.
, p. 637 - 645 (2020/12/07)
Catalytic cross-coupling is a valuable tool for forming new carbon-carbon and carbon-heteroatom bonds, allowing access to a variety of structurally diverse compounds. However, for this methodology to reach its full potential, precise control over all competing cross-coupling sites in poly-functionalised building blocks is required. Carbon-fluorine bonds are one of the most stable bonds in organic chemistry, with oxidative addition at C?F being much more difficult than at other C-halide bonds. As such, the development of methods to chemoselectively functionalise the C?F position in poly-halogenated arenes would be very challenging if selectivity was to be induced at the oxidative addition step. However, metal-halide complexes exhibit different trends in reactivity to the parent haloarenes, with metal-fluoride complexes known to be very reactive towards transmetalation. In this current work we sought to exploit the divergent reactivity of Ni?Cl and Ni?F intermediates to develop a chemoselective C?F functionalisation protocol, where selectivity is controlled by the transmetalation step. Our experimental studies highlight that such an approach is feasible, with a number of nickel catalysts shown to facilitate Hiyama cross-coupling of 1-fluoronapthalene under base free conditions, while no cross-coupling with 1-chloronapthalene occurred. Computational and experimental studies revealed the importance of reversible C?Cl oxidative addition for the development of selective C?F functionalisation, with ligand effects on the potential for reversibility also presented.
