Cut and paste! A Cu‐catalyzed aromaticCHcyanation with acetonitrile as the nitrile source by CCNcleavage has been developed (see scheme; TMEDA=N,N,N′,N′‐tetramethylethylenediamine). The reaction is catalytic in copper, and it is found that using (Me3Si)2 as an additive plays a critical role in promoting CCNcleavage and enhancing the reaction rate.
Cobalt-Catalyzed CH Cyanation of Arenes and Heteroarenes
作者:Jie Li、Lutz Ackermann
DOI:10.1002/anie.201409247
日期:2015.3.16
Carboxylate assistance proved to be the key for the success of efficient cobalt(III)‐catalyzedCH cyanations. Thus, an in situ generated cationic cobalt complex was identified as a versatile catalyst for the site‐selective synthesis of various aromatic and heteroaromatic nitriles with ample substrate scope.
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
A copper-mediated cyanation of heteroarene and arene C-H bonds has been developed, where ammonium iodide and DMF served as a safe cyanating combination. This procedure shows a broad substrate scope, allowing the facile access of 2-cyano indole, 1-cyano carbazole, 2-cyano pyrrole, and 2-cyano 1-pyridinyl benzene in high yields with good functional group tolerance.
We have developed a copper-mediated chelation-assisted direct aromatic ortho-C–H cyanation that uses AIBN as a safe cyanation reagent. The substrate scope included indoles, pyrroles, a carbazole, and a thiophene.