1592629-61-2Relevant academic research and scientific papers
Synthesis of o-Alkenylated 2-Arylbenzoxazoles via Rh-Catalyzed Oxidative Olefination of 2-Arylbenzoxazoles: Scope Investigation, Structural Features, and Mechanism Studies
Zhou, Quan,Zhang, Jing-Fan,Cao, Hui,Zhong, Rui,Hou, Xiu-Feng
, p. 12169 - 12180 (2016)
2-Arylbenzazoles are promising molecules for potential applications in medicine and material areas. Efficient protocols for direct regioselective functionalization of 2-arylbenzoxazoles are in high demand. Herein, we disclose a general method for selective ortho-olefination of 2-arylbenzo[d]oxazoles with alkenes enabled by versatile Cp*Rh(III) in high yields. This protocol features broad functional group tolerance and high regioselectivity. Intermolecular competition studies and kinetic isotope effect experiments imply that the oxidative olefination process occurs via an electrophilic C-H activation pathway. The molecular structure of the m-fluoro-substituted olefination product confirms regioselective C-H activation/olefination at the more hindered site in cases where the meta F atom or heteroatom substituent existed. Apparent torsion angles were observed in the structures of mono- and bis-olefination products, which resulted in distinct different chemical shifts of olefinic protons. Additionally, two gram-scale reactions and further transformation experiments demonstrate that this method is practical for synthesis of ortho-alkenylated 2-arylbenzoxazole derivatives.
Cooperative catalysis by palladium-nickel binary nanocluster for suzuki-miyaura reaction of ortho-heterocycle-tethered sterically hindered aryl bromides
Seth, Kapileswar,Purohit, Priyank,Chakraborti, Asit K.
supporting information, p. 2334 - 2337 (2014/05/20)
The palladium-nickel binary nanocluster is reported as a new catalyst system for Suzuki-Miyaura cross-coupling of ortho-heterocycle-tethered sterically hindered aryl bromides. The inferior results obtained with the reported Pd/Ni salts/complexes or individual Pd/Ni nanoparticles as catalyst reveal the cooperative catalytic effect of the Pd and Ni nanoparticles in the Pd-Ni nanocluster. The broad substrate scope with respect to variation of the 2-arylbenzoxazole moiety and boronic acids, which offers a means for diversity generation and catalyst recyclability, marks a distinct advantage.
