Methoxy or fluoro hydroindolenones and hydroquinolenones can be obtained by oxidation of the corresponding 4-substituted open-chain phenolds with C 6H 5I(OCOCF 3) 2 with methanol or pyridinium polyhydrogen fluoride followed by an intramolecular conjugate addition. The corresponding cyclo 2,5-hexadienones can be obtained directly by a similar oxidation of the bicyclic phenols.