[Br:1][C:2]1[C:3]2[CH:19]=[CH:18][CH:17]=[CH:16][C:4]=2[S:5][C:6]=1/[C:7](=[N:9]/[S:10]([C:12]([CH3:15])([CH3:14])[CH3:13])=[O:11])/[CH3:8].O.[BH4-].[Na+].C([O-])(O)=O.[Na+]>C1COCC1.CCOC(C)=O.CCCCCC>[Br:1][C:2]1[C:3]2[CH:19]=[CH:18][CH:17]=[CH:16][C:4]=2[S:5][C:6]=1[CH:7]([NH:9][S:10]([C:12]([CH3:14])([CH3:15])[CH3:13])=[O:11])[CH3:8]
To a solution of (E)-N-(1-(3-bromobenzo[b]thiophen-2-yl)ethylidene)-2-methylpropane-2-sulfinamide (1.35 g, 3.77 mmol) dissolved in THF (30 mL) and water (0.612 mL) cooled by a water-ice bath was added sodium borohydride (0.265 mL, 7.54 mmol) all in one portion. The reaction was stirred at low temperature for 30 min, and judged complete. To the reaction solution was added satd. aq. NaHCO3 and the resulting mixture stirred vigorously until gas evolution ceased. The aqueous layer was extracted with EtOAc, washed with brine, stirred over MgSO4, filtered and concentrated under reduced pressure to give a red oil. The product was isolated by column chromatography on a silica gel column using 30 to 70% gradient of EtOAc in hexane as eluent to give N-(1-(3-bromobenzo[b]thiophen-2-yl)ethyl)-2-methylpropane-2-sulfinamide as a pale yellow oil: 1H NMR (400 MHz, CDCl3) δ 1.24 (s, 10H), 1.63 (d, J=6.5 Hz, 3H), 3.85 (d, J=2.9 Hz, 1H), 5.16 (dd, J=6.7, 3.5 Hz, 1H), 7.35 (t, J=7.7 Hz, 1H), 7.41 (t, J=7.7 Hz, 1H), 7.76 (t, J=7.0 Hz, 2H). N-(1-(3-(3,5-Difluorophenyl)benzo[b]thiophen-2-yl)ethyl)-2-methylpropane-2-sulfinamide
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