Water → (R)-2-methyl-propane-2-sulfinic acid [(S)-1-(4-bromo-2-methyl-phenyl)-ethyl]amide

Lithium tri-sec-butylborohydride (1 mol/L in tetrahydrofuran, 59.2 mL) was added to a solution of (R)-2-methyl-propane-2-sulfinic acid [1-(4-bromo-2-methyl-phenyl)-ethylidene]-amide (6.24 g) in tetrahydrofuran (50 mL) chilled in an ice bath. The solution was stirred for 2 h while warming to room temperature in the cooling bath. The solution was then cooled again in an ice bath prior to the careful addition of water. The resulting mixture was extracted with ethyl acetate and the combined extracts were washed with water, saturated aqueous NaHCO3 solution, and brine. After drying (MgSO4) and evaporating the solvent, the title compound was obtained that was directly submitted to the next reaction step. Yield: 8.85 g (ca. 75% pure); Mass spectrum (ESI−): m/z=318/320 (Br) [M+H]+.