Aqueous Ammonia as a New Activator for Sonogashira Coupling

Abstract

Abstract Sonogashira coupling, which is a coupling reaction of terminal alkynes with organic halides, takes place with dilute aqueous ammonia as an activator. The reaction of several terminal alkynes and aryl iodides in the presence of small excess of aqueous ammonia at room temperature furnishes the cross-coupling product in good-to-excellent yields. A water-soluble amine with a high boiling point is alternatively employed for reactions at higher temperatures. A related coupling reaction in the presence of carbon monoxide also proceeded at room temperature and under ambient pressure to afford α,β-alkynyl ketones efficiently.