Metal-free synthesis of 1,3,5-trisubstituted benzenes by the cyclotrimerization of enaminones or alkynes in water

The cyclotrimerization reactions of enaminones and electron deficient terminal alkynes have been efficiently performed in water in the presence of only a small amount of lactic acid. The reactions led to the green synthesis of a variety of 1,3,5-triacylbenzenes without using any metal as catalyst. Brief investigation on different elaboration of the triacylbenzene product demonstrated the versatile synthetic application of these 1,3,5-triacylbenzenes.