Synthesis of 2‐Aminopyridines via Cobalt‐Catalyzed Cycloaddition of Diynes with N‐Substituted and N‐Unsubstituted Cyanamides

Abstract

AbstractReactivity of nitriles in a CoCl2−6H2O/dppe/Zn‐catalyzed diyne‐nitrile cycloaddition was explored through the competitive reactions of a diyne with two different nitriles, and it was found that cyanamides are good substrates, and the reaction yielded 2‐aminopyridines. Notably, N‐unsubstituted cyanamide (H2N−CN) could be used for the reaction with 1,6‐diynes to afford the corresponding N‐unsubstituted 2‐aminopyridines, which cannot be prepared via other catalytic reactions and are versatile intermediates for further transformations such as the synthesis of 2‐substituted pyridines and 6,7‐annulated imidazo[1,2‐a]pyridines.