1433900-99-2Relevant academic research and scientific papers
Copper-catalysed direct radical alkenylation of alkyl bromides
Zhang, Xu,Yi, Hong,Liao, Zhixiong,Zhang, Guoting,Fan, Chao,Qin, Chu,Liu, Jie,Lei, Aiwen
, p. 6790 - 6793 (2014)
A copper-catalysed direct radical alkenylation of various benzyl bromides and α-carbonyl alkyl bromides has been developed. Compared with the recent radical alkenylations which mostly focused on secondary or tertiary alkyl halides, this transformation shows good reactivity to primary alkyl halides and tertiary, secondary alkyl halides were also tolerated. The key initiation step of this transformation is a copper-induced single-electron reduction of C-Br bonds to generate alkyl radical species. This journal is the Partner Organisations 2014.
Ruthenium-Catalyzed Heck-Type Alkenylation of Alkyl Bromides
Mu?oz-Molina, José María,Pérez, Pedro J.
, p. 8289 - 8296 (2019/06/24)
The complex [CpRuCl(PPh3)2] displays a high catalytic activity for the Heck-type alkenylation of alkyl bromides in the first example using this metal under thermal conditions. The coupling reaction proceeds efficiently with a variety of functionalized tertiary, secondary, and primary alkyl bromides. The presence of Hünig's base has been revealed to be crucial for this transformation. Preliminary mechanistic studies support the participation of alkyl radicals in the reaction.
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.
