C-H Bond Functionalization With Isocyanides-Study On The Synthesis Of Imidazoles Using Silver Catalysis

C-H bond functionalization represents one of the most active and promising research field and is also regarded as one of the most powerful methods in organic chemistry. Considering that C-H bonds are ubiquitous in nature and organic molecules, this strategy has become an attractive alternative to form carbon-carbon and carbon-heteroatom bond. In general, such C-H bond transformations reduce the waste production and provide an atom economical route to the synthetic reactions. This research field has a long history and has always been the focus in the study of chemists.As an important synthon, isocyanides have been particularly useful for the synthesis of various nitrogen containing componds, such as pyrroles, indoles, and quinolines. Isocyanides often participate in multicomponent reactions, such as Passerini and Ugi reactions. In recent years, the field of C-H bond activation and functionalization involving isocyanides, especially catalyzed by transition-metal catalysts, is rapidly expanding and many new developments are achieved. This strategy is used for the synthesis of various nitrogen-containing componds, such as imines, amides, pyrroles, indoles, quinolines, etc.Imidazoles are one of the important classes of heterocyclic compounds because of their wide utilities in organic synthesis. Besides, they are often seen as a building block in natural and biologically active compounds. Hence, many methodologies have been developed for constructing imidazole rings. On the other hand, imidazole having a specific substitution pattern, especially 1,4-disubstituted imidazoles is particularly difficult to be synthesized. As the continuation of research our group discovered a silver catalyzed new type of cross coupling reaction between active methylene compounds and isocyanides via C-H functionalization. After that, we realize the cross coupling reaction between two different isocyanides. We use the tosylmethyl isocyanide as the starting material, realized the cycloaddition reaction of two different isocyanides for the synthesis of 1,4-disubstituted imidazoles employing silver carbonate as the catalyst.