58743-78-5Relevant articles and documents
The site-selectivity and mechanism of Pd-catalyzed C(sp2)-H arylation of simple arenes
Kim, Daeun,Choi, Geunho,Kim, Weonjeong,Kim, Dongwook,Kang, Youn K.,Hong, Soon Hyeok
, p. 363 - 373 (2021/01/14)
Control over site-selectivity is a critical challenge for practical application of catalytic C-H functionalization reactions in organic synthesis. Despite the seminal breakthrough of the Pd-catalyzed C(sp2)-H arylation of simple arenes via a concerted metalation-deprotonation (CMD) pathway in 2006, understanding the site-selectivity of the reaction still remains elusive. Here, we have comprehensively investigated the scope, site-selectivity, and mechanism of the Pd-catalyzed direct C-H arylation reaction of simple arenes. Counterintuitively, electron-rich arenes preferably undergo meta-arylation without the need for a specifically designed directing group, whereas electron-deficient arenes bearing fluoro or cyano groups exhibit high ortho-selectivity and electron-deficient arenes bearing bulky electron-withdrawing groups favor the meta-product. Comprehensive mechanistic investigations through a combination of kinetic measurements and stoichiometric experiments using arylpalladium complexes have revealed that the Pd-based catalytic system works via a cooperative bimetallic mechanism, not the originally proposed monometallic CMD mechanism, regardless of the presence of a strongly coordinating L-type ligand. Notably, the transmetalation step, which is influenced by a potassium cation, is suggested as the selectivity-determining step.
Atom-efficient Pd-catalyzed cross-couplings of chloroarenes with triarylbismuth reagents
Rao, Maddali L.N.,Meka, Suresh
supporting information, (2019/07/30)
Various Pd-catalyzed protocols have been developed for the atom-efficient cross-coupling of chloroarenes with triarylbismuth reagents. Using the developed protocols, an efficient synthesis of unsymmetrical biaryls in good to excellent yields was achieved by employing electron-deficient chloroarenes and a range of triarylbismuth reagents.
CuPd nanoparticles as a catalyst in carbon-carbon cross-coupling reactions by a facile oleylamine synthesis
Smith, Sarah E.,Siamaki, Ali R.,Gupton, B. Frank,Carpenter, Everett E.
, p. 91541 - 91545 (2016/10/11)
CuPd bi-metallic nanoparticles were synthesized in oleylamine without the use of additional surfactants, ligands, or reducing agents. The alloyed nanoparticles showed high catalytic activity in Suzuki cross-coupling reactions with excellent turnover number (6000) and turnover frequency of 72:000 h-1 under microwave irradiation. These nanoparticles were successfully utilized in a Suzuki coupling reaction with a diverse range of functionalized substrates. The catalyst also demonstrated multiple recyclability for Suzuki coupling reactions. The CuPd nanoparticles have also probed the utility in other cross-coupling reactions such as Heck and Sonogashira coupling reactions. According to the XPS data, two oxidation states of each metal exist on the surface of the nanoparticle. This is advantageous especially for Sonogashira cross-coupling reactions because having Cu+ present on the surface of the catalyst eliminates the need for a copper salt to stabilize the alkyne during the reaction.