The reaction mixture was then diluted with sat. aq. NH4Cl (30 mL), and the layers were separated. The aqueous layer was extracted with EtOAc (3 x 25 mL). The combined organic extracts were washed with brine (50 mL), dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure by rotary evaporation to provide SI-7 as a colorless solid. The compound was used without further purification. An analytically pure sample could be obtained through purification by flash column chromatography on silica gel (10% EtOAc/hexanes to 25% EtOAc/hexanes).