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5. To a solution of corannulene (100 mg, 0.4 mmol) in 50 mL of chloroform were added 10 mL of a 50% aqueous solution of NaOH and tetrabutylammonium hydrogen sulfate (20 mg) as a phase transfer catalyst. The mixture was stirred at room temperature for 20 h. The resulting brown solution was poured into 200 mL of water and extracted with chloroform (3×15 mL). The combined organic solutions were dried over anhydrous magnesium sulfate, and the solvent was removed under reduced pressure to give a dark brown solid. The crude product (ca. 105 mg) contains ca. 90% of corannulene, 8% of 2 and 2% of 3 (as determined by 1H NMR spectroscopy). Column chromatography on neutral alumina with 6:1 pentane:ether as eluant followed by preparative TLC (on silica gel with 6:1 pentane:ether as eluant) afforded relatively pure samples of 2 and 3.