935552-89-9Relevant 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.
A one-pot, single-solvent process for tandem, catalyzed C-H borylation-Suzuki-Miyaura cross-coupling sequences
Harrisson, Peter,Morris, James,Steel, Patrick G.,Marder, Todd B.
experimental part, p. 147 - 150 (2009/05/30)
Methyl tert-butyl ether is a suitable solvent for iridium-catalyzed C-H borylation followed, in the same pot, by palladium-catalyzed Suzuki-Miyaura cross-coupling sequences, giving high yields of biaryls. Georg Thieme Verlag Stuttgart.
Pd-catalyzed Kumada-Corriu cross-coupling reactions at low temperatures allow the use of Knochel-type Grignard reagents
Martin, Ruben,Buchwald, Stephen L.
, p. 3844 - 3845 (2008/02/02)
A catalyst system able to operate at temperatures as low as -65 °C for the Pd-catalyzed Kumada-Corriu cross-coupling reaction is described. This unprecedented level of activity allows the use of highly functionalized (Knochel-type) Grignard reagents. Additionally, the tolerance of the protocol toward a wide variety of functional groups allows for the synthesis of valuable compounds, including heterocyclic or polyfluoro biaryls. Copyright
