Transition metal-free approach for the synthesis of N-arylated piperidones and its ketals from ketenedithioacetal

N-Arylated piperidones were present as pharmacophores in many pharmaceuticals and useful precursors for the construction of new important molecules. We have developed a transition metal-free, cost-effective and mild approach for the synthesis of N-arylated/heteroarylated piperidones and its ketal by using ketal of piperidones and 2-oxo-5,6-dihydro-2H-benzo[h]chromene-3-carbonitriles as precursors. The desired product was achieved in 2 steps including amination of 2-oxo-5,6-dihydro-2H-benzo[h]chromene-3-carbonitriles from piperidone followed by ring transformation using a suitable nucleophile source. We have successfully tethered functionalized dihydrophenanthrenes, hydrobenzo[c]phenanthrenes and benzoquinolines at N-piperidinone under transition metal free conditions.