A 50 mL round-bottom flask was charged with a magnetic stir-bar, 7 (0.3 g, 1.05 mmol, 1 equiv.) and anhydrous CH2Cl2 (10 mL). The reaction flask was cooled to 0 °C using an ice-water bath. Trimethyl orthoformate (1.15 mL, 1.12 g, 10.5 mmol, 10 equiv.), ethylene glycol (0.6 mL, 0.67 g, 10.7 mmol, 10 equiv.), and p-TsOH•H2O (18 mg, 0.09 mmol, 0.1 equiv.) were added at 0 °C. The reaction mixture was warmed to room temperature over a period of 2 hours. Following this time, the reaction mixture was cooled to 0 °C using an ice-water bath and quenched with chilled H2O (15 mL). After transferring to a separatory funnel, the mixture was extracted with CH2Cl2 (2 X 15 mL). The combined organic layers were washed once with saturated aqueous NaCl solution and dried with Na2SO4. After the solvent was removed under reduced pressure, the resulting residue was purified by chromatography on silica gel by eluting with hexane/ethyl acetate (85:15) to afford 8 (colorless oil, 0.311 g, 0.95 mmol, 90% yield).