1380341-68-3Relevant academic research and scientific papers
Visible-light photocatalytic radical alkenylation of a-carbonyl alkyl bromides and benzyl bromides
Liu, Qiang,Yi, Hong,Liu, Jie,Yang, Yuhong,Zhang, Xu,Zeng, Ziqi,Lei, Aiwen
supporting information, p. 5120 - 5126 (2013/06/27)
Through the use of [Ru- (bpy)3Cl2] (bpy=2,2'-bipyridine) and [Ir(ppy)3] (ppy=phenylpyridine) as photocatalysts, we have achieved the first example of visible-light photocatalytic radical alkenylation of various acarbonyl alkyl bromides and benzyl bromides to furnish a-vinyl carbonyls and allylbenzene derivatives, prominent structural elements of many bioactive molecules. Specifically, this transformation is regiospecific and can tolerate primary, secondary, and even tertiary alkyl halides that bear b-hydrides, which can be challenging with traditional palladium-catalyzed approaches. The key initiation step of this transformation is visible-light-induced single-electron reduction of CBr bonds to generate alkyl radical species promoted by photocatalysts. The following carboncarbon bond-forming step involves a radical addition step rather than a metal-mediated process, thereby avoiding the undesired b-hydride elimination side reaction. Moreover, we propose that the Ru and Ir photocatalysts play a dual role in the catalytic system: they absorb energy from the visible light to facilitate the reaction process and act as a medium of electron transfer to activate the alkyl halides more effectively. Overall, this photoredox catalysis method opens new synthetic opportunities for the efficient alkenylation of alkyl halides that contain b-hydrides under mild conditions.
Nickel-catalyzed heck-type alkenylation of secondary and tertiary α-carbonyl alkyl bromides
Liu, Chao,Tang, Shan,Liu, Dong,Yuan, Jiwen,Zheng, Liwei,Meng, Lingkui,Lei, Aiwen
supporting information; experimental part, p. 3638 - 3641 (2012/05/20)
Ni made it! A novel Heck-type reaction of secondary and tertiary α-carbonyl alkyl bromides, most likely involving a radical process, was achieved through the use of a nickel catalyst. Various substituted styrenes and 1,1-diaryl alkenes were utilized as substrates to easily construct α-alkenyl carbonyl compounds with tertiary or quaternary carbon centers. A catalytic cycle involving NiI/NiII is proposed based on our experimental results. EWG=electron-withdrawing group.
