Palladium-free copper-catalyzed Sonogashira cross-coupling at room temperature

摘要

We have developed an efficient method for the palladium-free copper-catalyzed Sonogashira cross-coupling of o-iodo-acetanilide derivatives with alkynes at room temperature; the corresponding coupling products were obtained in good to excellent yields using copper(I) iodide/N-methylpyrrolidine-2-carboxamide as the catalyst. This inexpensive catalyst system has high tolerance towards various Functional groups in the substrates. This represents the lowest reaction temperatures for copper-catalyzed Sonogashira cross-coupling thus far.