The general procedure for the synthesis of 3-methoxy-tetrahydro-2H-pyran-4-one from the compound (CAS: 624734-16-3) was as follows: intermediate 3 (3.0 g, 17.04 mmol) was dissolved in a mixed solvent of tetrahydrofuran/water (60 mL/10 mL) and concentrated hydrochloric acid (6 mL) was added. The reaction mixture was stirred at room temperature for 1 hour. Upon completion of the reaction, the mixture was concentrated under reduced pressure to remove the tetrahydrofuran. Subsequently, the aqueous layer was extracted with ether (6 x 50 mL). The organic phases were combined, dried with anhydrous sodium sulfate, filtered and the solvent evaporated under reduced pressure to give Intermediate 24 (1.75 g, 79% yield) as a clear oil. The product was characterized by 1H NMR (500 MHz, CDCl3) with chemical shifts δ of 4.23 (ddd, J = 1.2, 11.4, 12.4 Hz, 1H), 4.15-4.09 (m, 1H), 3.82 (dd, J = 5.95, 8.7 Hz, 1H), 3.74 (ddd, J = 5.5, 8.5, 13.6 Hz. 1H), 3.56 (dd, J = 8.8, 11.3 Hz, 1H), 3.50 (s, 3H), 2.61 (app dd, J = 5.0, 8.9 Hz, 2H).
