An efficient palladium-catalyzed copper- and amine-free Sonogashira coupling reaction of aryl bromides and chlorides was studied using a sterically hindered monooxychlorophosphine as new ligand.The use of 2 mol%Pd(OAc)_2 in the presence of K_2CO_3 allows the coupling reaction to proceed at mild condition with good to excellent yields. An efficient palladium-catalyzed copper- and amine-free Sonogashira coupling reaction of aryl bromides and chlorides was studied using a sterically hindered monooxychlorophosphine as a new ligand. The use of 2 mol% Pd (OAc) _2 in the presence of K_2CO_3 allows the coupling reaction to proceed at mild condition with good to excellent yields.