4-(Chloromethyl)benzoyl chloride (105 mg, 0.558 mmol) was added to a stirred solution of 2-dimethylamino-6-methoxybenzo[b]thiophene (105 mg, 0.507 mmol) in chlorobenzene (1 mL) under nitrogen. The resultant mixture was heated in an oil bath at 110° C. for 2.5 h. The mixture was cooled to 0° C., treated with pyrrolidine (5 mL), then allowed to stir at room temperature for 2 h. After dilution with THF (20 mL), the mixture was washed with saturated aqueous NaHCO3 (5 mL). The organic layer was dried over MgSO4, filtered, concentrated, and chromatographed on silica [gradient 20-40% EtOAc in hexanes, then 0-10% EtOH/Et3N (2/1) in THF/hexanes (1/1)] to give 148 mg (74%) of the ketone as a foam.
