Facile One-Pot Synthesis of Oxo-Xanthenes under Microwave Irradiation

A convenient diversity oriented synthetic procedure for the construction of various oxo-xanthenes such as 12- aryl-8,9,10,12-tetrahydrobenzo[a]-xanthene-11-ones, 9-aryl-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H)-diones and 9- substituted-2,3,4,9-tetrahydro-1H-xanthen-1-ones has been developed by using p-dodecylbenzenesulfonic acid as an efficient Brønsted acid catalyst under solvent-free microwave conditions. The present methodology is found to be operationally simple and demonstrates many advantages including shorter reaction times, easy purification steps and good to excellent yields of the target products.