Cobalt-Catalyzed Carbo- and Hydrocyanation of Alkynes via C-CN Bond Activation

Cobalt-catalyzed carbo- and hydrocyanation reac-tions of alkynes via C-CN bond cleavage of organic cyanides arereported. A low-valent cobalt-diphosphine catalyst generated byreduction with Zn promotes the arylcyanation of alkynes withtrans-selectivity. By contrast, the addition of Zn(OTf)2to thiscatalytic system not only accelerates the transformation but alsoswitches the stereoselectivity, affordingcis-arylcyanation products.The present catalytic systems prove to be effective foralkenylcyanation using alkenyl cyanides as well as for transferhydrocyanation using propionitrile as the HCN surrogate. Experimental and computational studies on arylcyanation have beenperformed to gain insight into the reaction pathways, including the possible origin of the stereodivergence under cobalt and cobalt/zinc catalysis

Automated summary

This article reports a cobalt-catalyzed carbo- and hydrocyanation reaction of alkynes, which involves C-CN bond cleavage of organic cyanides. A low-valent cobalt-diphosphine catalyst, generated by reduction with Zn, is used to promote the arylcyanation of alkynes with trans-selectivity. Additionally, the addition of Zn(OTf)2 to the catalytic system accelerates the reaction and switches the stereoselectivity.