To a suspension of 1.1 g of magnesium shavings and a few drops of dibromoethane in 30 ml of ether was added a solution of 7.9 g of p-bromofluorobenzene in 20 ml of ether at a rate to maintain reflux of the mixture. After the addition was complete, the mixture was slowly diluted with 30 ml of tetrahydrofuran and then a solution of 5 g of 1-[3-(6-fluoro-1,2-benzisoxazol-3-yl)propyl]-4-piperidone in 30 ml of tetrahydrofuran was slowly added. After one hr, the mixture was diluted with ether, poured into 400 ml of saturated ammonium chloride solution and extracted with ether. The organic extracts were washed with water (2×), saturated sodium chloride solution and dried over anhydrous magnesium sulfate, filtered and concentrated. The residue was recrystallized from hexanes/ether to give 3.6 g (54%) of product, mp 100°-101° C.
