To a cooled solution (-78° C.) of oxalyl chloride (3.06 mL, 35.1 mmol, 2 eq) in methylene chloride (100 mL) under nitrogen was added distilled dimethylsulfoxide (5.00 mL, 70.2 mmol, 4 eq). After 10 min 1-(2-chloro-9,10-dihydro-9,10-methanoanthracen-9-ylmethyl) piperidin-4-ol (described in example 11) (5.96 g, 17.5 mmol) was added as a methylene chloride solution (10 mL). The reaction was stirred at -78° C. for 30 min prior to the addition of triethylamine (19.6 mL, 140 mmol, 8 eq). The cooling bath was removed and the reaction warmed to room temperature over 1.5 h. The reaction was poured into 2.5N NaOH (100 mL) and the aqueous phase extracted with methylene chloride (3×100 mL). Combined organic extracts were dried over anhydrous magnesium sulfate, filtered, and reduced to an oil. The crude reaction mixture was purified by flash chromatography over silica gel (400 mL, eluent: 20% ethyl acetate in hexane) to yield 5.53 g (93%) of the title compound. TLC analysis (Rf 0.21, 20% ethyl acetate in hexane). 1H NMR (CDCl3, 250 MHz) 7.26 (m, 1H), 7.13 (m, 3H), 6.95 (m, 3H), 4.28 (s, 1H), 3.49 (s, 2H), 2.94 (t, J=6.1 Hz, 4H), 2.62 (s, 2H), 2.43 (t, J=6.0 Hz, 4H) MS (CI, CH4) m/z 338 (M+1,100), 340 (35), 366 (M+29,31).
