1601462-01-4Relevant academic research and scientific papers
Direct C-H Arylation of Heteroarenes with Copper Impregnated on Magnetite as a Reusable Catalyst: Evidence for CuO Nanoparticle Catalysis in Solution
Vásquez-Céspedes, Suhelen,Chepiga, Kathryn M.,M?ller, Nadja,Sch?fer, Andreas H.,Glorius, Frank
, p. 5954 - 5961 (2016/09/09)
A reusable copper-based catalyst system was employed for the direct arylation of electron-rich heteroarenes. Under mild and operationally simple reaction conditions good yields and selectivities were obtained using diaryliodonium salts as coupling partners. A combination of experimental methods including kinetic studies, filtration tests, and a series of analytical tools (TXRF, ICP-MS, SEM, XPS, TEM, EFTEM) provide evidence for catalytically active soluble nanoparticles formed from an amorphous heterogeneous precursor. Mechanistic studies hint at a redox-neutral process which promotes counterion dissociation from the diaryliodonium salt by a copper(II) oxide species.
Pd/C as a catalyst for completely regioselective c=h functionalization of thiophenes under mild conditions
Tang, Dan-Tam D.,Collins, Karl D.,Ernst, Johannes B.,Glorius, Frank
, p. 1809 - 1813 (2014/03/21)
The completely C3-selective arylation of thiophenes and benzo[b]thiophenes was achieved by using Pd/C as a heterogeneous catalyst without ligands or additives under mild reaction conditions. The practicability of this transformation is demonstrated by notable functional group tolerance and the insensitivity of the reaction to H2O and air. This method is also applicable to nitrogen- and oxygen-containing heterocycles, yielding the corresponding C2-arylated products. Three-phase tests along with Hg-poisoning and hot-filtration tests suggest that the catalytically active species is heterogeneous in nature. I+ can do better! Pd/C can be used without ligands or additives to catalyze the completely C3-selective arylation of diversely substituted thiophenes and benzo[b]thiophenes under mild reaction conditions. The physical nature of the catalytic species was investigated and the mechanism was studied. Relative rate data generated in a "robustness screen" were used to design a complex substrate that undergoes highly chemoselective sequential functionalization. Copyright
