N-Unsubstituted β-lactams react with a molecule of aryne by insertion into the amide bond to form a 2, 3-dihydroquinolin-4-one, which subsequently reacts with another molecule of aryne to form an acridone by extrusion of a molecule of ethylene. 2, 3-Dihydroquinolin-4- ones react under the same reaction conditions to afford identical results. This is the first example of ethylene extrusion in aryne chemistry.
