[Br:1][C:2]1[C:3]2[C:13]([CH3:14])=[CH:12][CH:11]=[CH:10][C:4]=2[S:5][C:6]=1[C:7](O)=[O:8].[BH4-].[BH4-].[BH4-].[BH4-].[Na+].[Na+].[Na+].[Na+].O>S(Cl)(Cl)=O.C(OCC)(=O)C>[Br:1][C:2]1[C:3]2[C:13]([CH3:14])=[CH:12][CH:11]=[CH:10][C:4]=2[S:5][C:6]=1[CH2:7][OH:8]A solution of 3-bromo-4-methyl-benzo[b]thiophene-2-carboxylic acid (23c) (420 mg, 1.55 mmol) in thionyl chloride (10 mL) was refluxed for 1 hour. Thionyl chloride was then evaporated under reduced pressure and the residue was diluted with dimethoxyethane (20 mL). Sodium tetraborohydride (70 mg, 1.85 mmol) was then added to the solution. After 1 hour, the mixture was hydrolyzed with water (5 mL) and diluted with ethyl acetate (20 mL). The organic layer was washed with brine (10 mL), dried over sodium sulfate, filtered and evaporated to dryness to afford the desired alcohol (23d) as a white solid without further purification (400 mg, 1.55 mmol, 100%).
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