A series of 3,4-disubstituted dihydroquinolin-2(1H)-ones have been synthesized via three-component reaction of 1,3-indandione with isatin derivatives and N-phenacyl pyridinium bromide salts in presence of triethylamine as basic reagent. This procedure affords a highly efficient route for accessing quinolones by ring expansion of isatin via a one-pot pathway. Products were obtained in good to moderate yield without requiring a chromatographic purification step.
