Borane;tetrahydrofuran → (R)-4-(4-(4-(2-(tert-Butyldiphenylsilyloxy)ethyl)piperazin-1-yl)-1-(phenylthio)butan-2-ylamino)-3-(trifluoromethylsulfonyl)benzenesulfonamide

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Reaction Steps

(R)-4-(4-(4-(2-(tert-Butyldiphenylsilyloxy)ethyl)piperazin-1-yl)-4-oxo-1-(phenylthio)butan-2-ylamino)-3-(trifluoromethyl sulfonyl)benzenesulfonamide (INTERMEDIATE 21, 0.98 g, 1.15 mmol) was dissolved in THF (4.6 ml), under a nitrogen atmosphere, and a solution of borane-THF complex (1M in THF; 6.93 ml, 6.93 mmol) was added. The mixture was diluted with NH3 in MeOH (7N, 20 ml) and stirred at room temperature overnight. The reaction mixture was concentrated under reduced pressure, diluted with EtOAc (75 ml), washed with water (40 ml), and dried (Na2SO4). Evaporation of the volatiles under reduced pressure afforded a concentrate, which was purified by column chromatography (ISCO, 40 g silica gel column, eluting with 0→100% EtOAc/hexanes) to provide the title compound (245 mg, yield: 25%).

Provenance & Evidence