Silver-Mediated Cyanation Of Terminal Alkynes

The cyano group is formed by a triple bond between a carbon atom and a nitrogen atom,and it is a strong electron-withdrawing group.Cyano compounds are a very widely used organic synthesis intermediate.Due to its unique chemical properties of cyano groups,it can be hydrolyzed to carboxyl groups and reduced to amino groups.Cyano compounds also have important applications in the synthesis of pharmaceuticals,agrochemicals,dyes,and multifunctional materials.Cyano groups are used to improve small organic molecules.There is an irreplaceable role in the performance of optoelectronic materials and conductive materials.Alkynyl compounds are a class of highly active organic synthesis intermediates.It not only exists in natural products,drugs,organic materials.At the same time,it has a good application value in the synthesis of heterocyclic compounds with biological activity and drug activity.The propargene nitrile compound has a wide range of uses in synthesis as a compound having both a cyano group and an alkyne group in the molecule.Not only has it received extensive attention in the industry,but the compounds obtained by derivatizing these two functional groups are also of great significance both chemically and biologically.It not only can synthesize a large number of drugs and biologically active compounds,but also can be easily converted into compounds containing multifunctional groups,such as nitrogencontaining heterocycles,amides,amines and the like.Therefore,the preparation method of the propargene compound has attracted wide attention from chemists.One type of method is to convert a propyne system to propargylnitrile with or without metal.Another method is the direct cyanation reaction of terminal alkynes.Such methods open up new ways to directly produce propionitrile using organic and inorganic chemicals.However,these methods are limited by the use of toxic cyanide,easily hydrolyzed reagents or harsh reaction conditions.Therefore,finding a method for synthesizing propargylnitrile from a safe,stable and simple starting material is very significant for modern organic synthesis.In this paper,starting from the simple terminal alkyne,direct cyanation of the terminal alkyne is achieved by a direct C-H bond cyanation reaction.Using the water as an additive and silver trifluoromethanesulfonate as a catalyst,we used a non-toxic,safe and easy-tohandle N-isocyanoiminotriphenylphosphine(NIITP)as the source of cyano groups.This method is characterized by simple,mild conditions,high yield,a wide range of substrates.