72093-41-5Relevant academic research and scientific papers
Ligand-Promoted Direct C-H Arylation of Simple Arenes: Evidence for a Cooperative Bimetallic Mechanism
Kim, Jaewoon,Hong, Soon Hyeok
, p. 3336 - 3343 (2017/06/09)
A highly efficient catalyst for the direct C-H arylation of simple arenes was developed on the basis of a palladium-diimine complex. The developed catalyst exhibited the highest turnover number reported to date for the direct arylation of benzene due to increased stability provided by the diimine ligand. The reaction was also performed using only 2-3 equiv of simple arenes. Mechanistic studies in combination with kinetic measurements, isotope effect experiments, synthesis of possible intermediates, and stoichiometric reactions suggested that this reaction follows a cooperative bimetallic mechanism.
Assessment of the intermediacy of arylpalladium carboxylate complexes in the direct arylation of benzene: Evidence for C-H bond cleavage by "ligandless" species
Tan, Yichen,Hartwig, John F.
supporting information; experimental part, p. 3308 - 3311 (2011/05/04)
Palladium-catalyzed direct arylations of benzene have been proposed to occur by the generation of a phosphine-ligated arylpalladium pivalate complex LPd(Ar)(OPiv) and reaction of this complex with benzene. We have isolated an example of the proposed intermediate and evaluated whether this complex does react with benzene to form the biaryl products of direct arylation. In contrast to the proposed mechanism, no biaryl product was formed from cleavage of the benzene C-H bond by LPd(Ar)(OPiv). However, reactions of LPd(Ar)(OPiv) with benzene and additives that displace or consume the phosphine ligand formed the arylated products in good yield, suggesting that a "ligandless" arylpalladium(II) carboxylate complex undergoes the C-H cleavage step. Consistent with this conclusion, we found that reactions catalyzed by Pd(OAc)2 without a ligand occur faster than, and with comparable selectivities to, reactions catalyzed by Pd(OAc)2 and a phosphine ligand.
A new and practical grignard-coupling-fluorination sequence: Synthesis of 2-aryl fluoroarenes
Anbarasan, Pazhamalai,Neumann, Helfried,Beller, Matthias
scheme or table, p. 1775 - 1778 (2011/03/19)
A new strategy for the synthesis of 2-aryl-and 2-heteroaryl fluoroarenes has been developed. An intermolecular domino Grignard-coupling-fluorination sequence affords a range of 2-fluorobiaryls from aryl bromides under mild conditions. This methodology can be further extended to the synthesis of 2′-aryl-2-fluorobiphenyls.
Structure-reactivity relationships in negishi cross-coupling reactions
Dong, Zhi-Bing,Manolikakes, Georg,Shi, Lei,Knochel, Paul,Mayr, Herbert
supporting information; experimental part, p. 248 - 253 (2010/03/30)
Competition experiments have been performed to determine the relative reactivities of substituted bromobenzenes and of different arylzinc reagents in the [Pd(PPh3)4]-catalyzed Negishi cross-coupling reaction in THF at 25 °C. The crosscoupling reactions are accelerated by electron acceptors in the bromobenzenes, the effect of which increases in the order ortho a larger effect than substituent variations in the arylzinc halides (ρ = -0.98).
