After the reaction mixture had stirred at room temperature for 3 hours, the reaction mixture was diluted with sat. aq. NH4Cl (5 mL) and H2O (15 mL), and the layers were separated. The aqueous layer was extracted with EtOAc (3 x 15 mL). The combined organic extracts were washed with brine (15 mL), dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure by rotary evaporation to provide a crude yellow foam. Purification by flash column chromatography on silica gel (hexanes/EtOAc 1:1.2) afforded SI-8 (61 mg, 54%, 7:1 dr) as a yellow solid.