A suspension of copper(II) oxide (0.96 g, 12.1 mmol) and anhydrous copper(II) chloride (3.2 g, 23.8 mmol) in acetone (80 mL) was heated to reflux. A solution of 230 (4.44 g, 10.0 mmol) in acetone (20 mL) and DMF (1.2 mL) was added dropwise over 5 min. After 90 min at reflux temperature, the reaction mixture was cooled to room temperature and filtered. The insoluble material was washed with CH2Cl2 (3×20 mL). The combined organic solutions were washed with aqueous 2 N Na2CO3 solution (50 mL), dried over anhydrous Na2SO4, and concentrated in vacuo. The residue was purified by column chromatography (silica gel; hexanes/acetone=80/20) to give 232 (2.5 g, 71%) as an oil. 1H NMR (CDCl3): δ 7.68-7.30 (m, 8H), 3.31 (s, 4H), 3.03 (s br., 2H), 2.65 (s, 4H), 0.88 (s; 12H). 13C NMR (CDCl3=77.00 ppm): δ 197.42, 139.06, 136.96, 134.60, 131.88, 127.78, 127.55, 70.39, 44.07, 36.30, 23.80. HRMS (LSIMS, nba): Calcd for C23H31O3 (MH+): 355.2273, found: 355.2263. HPLC: 94.5% pure.
