Copper-Mediated Direct Aryl C–H Cyanation with Azobisisobutyronitrile via a Free-Radical Pathway
摘要:
An unprecedented protocol for the copper-mediated direct cyanation of aryl C-H by employing 2,2'-azobisisobutyronitrwile (AIBN) as a free radical "CN" source is presented. The protocol not only provides a more efficient pathway for the synthesis of aryl nitriles in terms of the yields and the loading amount of copper salts but also, more importantly, represents a novel strategy for aryl C-H cyanation via a CN free-radical mechanism as compared to the CN anion-participating protocols often reported.
Copper-mediated C–H cyanation of (hetero)arenes with ethyl (ethoxymethylene)cyanoacetate as a cyanating agent
作者:Chaorong Qi、Xiaohan Hu、Huanfeng Jiang
DOI:10.1039/c7cc03384b
日期:——
A copper-mediated direct C–H cyanation reaction of (hetero)arenes with ethyl (ethoxymethylene)cyanoacetate as a safe cyanating agent has been developed.
Copper-catalyzed cyanation of arenes using benzyl nitrile as a cyanide anion surrogate
作者:Jisong Jin、Qiaodong Wen、Ping Lu、Yanguang Wang
DOI:10.1039/c2cc35046g
日期:——
The copper-catalyzedcyanation of arenes using benzyl nitrile as a cyanide anion surrogate furnishes aromatic nitriles in moderate to good yields. The cascade process involves a copper-catalyzed aerobic C-Hoxidation, a retro-cyanohydrination, and a copper-catalyzed aerobic oxidativeC-H functionalization.
A chelation-assistedpalladium-catalyzed ortho-cyanation of the sp2 C−H bond by CuCN provided aromatic nitriles in moderate to good yields. Notably, the reaction could be conducted on a 10 mmol scale. The key intermediate of the natural product of Menispermum dauricum DC was concisely synthesized by the procedure. This new approach represents an exceedingly practical method for the synthesis of aromatic
Co(III)-Catalyzed C–H Activation/Formal S<sub>N</sub>-Type Reactions: Selective and Efficient Cyanation, Halogenation, and Allylation
作者:Da-Gang Yu、Tobias Gensch、Francisco de Azambuja、Suhelen Vásquez-Céspedes、Frank Glorius
DOI:10.1021/ja511011m
日期:2014.12.24
The first cobalt-catalyzed cyanation, halogenation, and allylation via C-Hactivation have been realized. These formal SN-type reactions generate valuable (hetero)aryl/alkenyl nitriles, iodides, and bromides as well as allylated indoles using a bench-stable Co(III) catalyst. High regio- and mono-selectivity were achieved for these reactions. Additionally, allylation proceeded efficiently with a turnover
An iron-mediated direct cyanation of indole and 2-arylpyridine C-H bonds is described. Notably, trimethoxybenzene reacted smoothly under the procedure, forming a C-CN bond via C-H bond cleavage without chelation assistance.