in vacuo the crude product was purified by flash column chromatography on silica gel 50 100 etoac in hexanes then 2 98 et 3 n etoac then 2 20 80 et 3 n meoh ch 2 cl 2 to yield intermediate 10 157 mg 84 as off white solid 1 h nmr chloroform d u03b4 7 61 dd j 3 7 1 3 hz 1h 7 44 dd j 5 0 1 2 hz 1h 6 96 7 03 m 2h 6 83 dd j 7 6 1 5 hz 1h 6 56 dd j 7 6 6 2 hz 1h to a solution of intermediate 9 111 mg 0 35 mmol in meoh 15 ml was added aqueous nh 4 cl 15 ml and zinc dust 0 56 g 8 7 mmol the mixture was stirred at room temperature for 2 h filtered and extracted with etoac the organic layer was washed with brine dried over na 2 so 4 and concentrated in vacuo the crude product was purified by flash column chromatography on silica gel 30 100 etoac in hexanes then 10 meoh in ch 2 cl 2 to yield intermediate 11 75 mg 75 c 9 h 8 cln 3 o 2 s 2 289 8 ms esi u2212 288 290 m u2212 h u2212 sulfonamide formation to a solution of intermediate 2 80 mg 0 21 mmol and dmap 5 1 mg 0 042 mmol 0 2 eq in chcl 3 0 8 ml and.