A novel protocol for the synthesis of α-aryl nitriles has been successfully achieved via a copper-catalyzed cyanation of N-tosylhydrazones employing thiocyanate as the source of cyanide. The features of this method include a convenient operation, readily available substrates, low-toxicity thiocyanate salts, and a broad substrate scope.
Pyrrolo-imidazo[1,2-<i>a</i>]pyridine Scaffolds through a Sequential Coupling of <i>N</i>-Tosylhydrazones with Imidazopyridines and Reductive Cadogan Annulation, Synthetic Scope, and Application
作者:Kena Zhang、Abderrahman El Bouakher、Helene Levaique、Jerome Bignon、Pascal Retailleau、Mouad Alami、Abdallah Hamze
DOI:10.1021/acs.joc.9b02018
日期:2019.11.1
of 3-phenyl-1H-pyrrolo-imidazo[1,2-a]pyridine backbone is described. The reaction starts from the coupling between N-tosylhydrazones and 2-chloro-3-nitroimidazo[1,2-a]pyridines leading to the formation of 3-nitro-2-(arylvinyl)imidazo[1,2-a]pyridinederivatives. Optimization of Cadogan-reductive conditions allowed the conversion of the obtained nitro derivative to a new scaffold of the type 3-aryl-
Selective construction of 2-substituted benzothiazoles from o-iodoaniline derivatives S8 and N-tosylhydrazone via a copper-promoted [3 + 1 + 1]-type cyclization reaction has been realized. In the protocol, the carbon atom on N-tosylhydrazone could be regulated to construct benzothiazole by changing the reaction system. Furthermore, the transformation has achieved the construction of multiple carbon-heteroatom
A new one‐pot palladium‐catalyzed process between N‐tosylhydrazones, N‐(dihalophenyl)‐imidates, and amines was designed. This reaction involves Barluenga cross‐coupling and N‐arylation followed by cyclization to produce functionalized benzimidazoles. During this transformation, one CC bond and two CN bonds were created by a single palladium‐catalyzed reaction. Depending on the starting materials
NNNifty targets: In a straightforward copper‐mediated synthesis of 1,4‐disubstituted and 1,4,5‐trisubstituted 1,2,3‐triazoles, readily available aniline and N‐tosylhydrazone substrates underwent cyclization through CN and NN bond formation (see scheme; Piv=pivaloyl, Ts=p‐toluenesulfonyl). This method enables the preparation of 1,2,3‐triazoles with high efficiency under mild conditions without the