Electro- and Mechanochemical N -Cyanomethylation and N -Selenylation of a Diverse Array of Biorelevant Aryl(Heteroaryl) Hydrazones: A Robust Dual Green Synthetic Approach

Abstract We herein disclose a dual synthetic approach involving electrochemical and mechanochemical strategies for the N-cyanomethylation and N-selenylation of aryl(heteroaryl) hydrazones, thereby accessing a new series of diversely functionalized aryl(heteroaryl) hydrazinyl acetonitriles and aryl(heteroaryl) hydrazinyl phenylselenides, respectively. Both methods are fruitfully applicable to the N-cyanomethylation of a group of N-heterocycles. This dual approach highlights the synergy between electrochemistry and mechanochemistry as green and sustainable platforms for constructing value-added nitrile- and organoselenium molecules relevant to medicinal and materials chemistry. The key advantages of these newly developed, green chemistry-driven methodologies include mild reaction conditions using green energy tools, the avoidance of transition metal catalysts, external oxidants, hazardous cyanide sources, and reacting solvents (mechanochemical), a broad substrate scope with excellent functional-group tolerance, good to excellent yields, short reaction times (in minutes), the reusability of the solid surface (mechanochemical), operational simplicity, low E-factors (mechanochemistry), higher Faradaic efficiency (electrochemical), and eco-friendliness. Gram-scale synthesis and late-stage synthetic application of the hydrazinyl acetonitrile compound have also been demonstrated.