Representative procedure: synthesis of 6-methylbenzodihydropyran-4-one (7a). To 2,3-dihydro-4H-chromen-4-one (4a, 1.20 g, 6.18 mmol) in an acetonitrile-water mixture (10 mL, 1:2, v/v) was added cerium ammonium nitrate (CAN, 5 g, 9.27 mmol). The reaction mixture was heated to 70 °C under stirring, maintained for 30 min and subsequently cooled to room temperature. The reaction mixture was diluted with water and extracted with ether (3 x 20 mL). The combined organic layers were washed with saturated sodium bicarbonate solution (20 mL) and subsequently dried over anhydrous magnesium sulfate. After filtration, the mixture was concentrated under reduced pressure to give 6-methylbenzodihydropyran-4-one as a yellow oil (0.64 g, 70% yield).
![1,3-Dioxolane, 2-[2-(4-methylphenoxy)ethyl]-](/CAS/20210305/GIF/1225533-42-5.gif)
