Copper-Catalyzed Synthesis of Quinoxalines with <i>o-</i>Phenylenediamine and Terminal Alkyne in the Presence of Bases

A novel way of synthesizing quinoxalines efficiently through cyclization of <i>o-</i>phenylenediamine and terminal alkyne by Cu(II) and bases is developed. This reaction proceeds smoothly to give the products in moderate to good yields.