A slurry of AlCl3 (2.74 g, 20.76 mmol) in CH2Cl2 (21 ml) was treated with tert-butylaminoborane (3.57 g, 41.52 mmol) at 0° C. and stirred for 30 minutes. Next, a solution of the product from step e) (1.96 g, 6.92 mmol) in CH2Cl2 (15 ml) was added dropwise to the AlCl3/borane solution. After 2 hours at 0° C., the crude reaction mixture was poured into cold 10% HCl, treated with 2 M NaOH to pH 12 and extracted with CH2Cl2 (3×75 ml). The combined organic extracts were washed with brine (75 ml), dried (MgSO4), and the solvent evaporated in vacuo leaving the crude product that was purified by silica-gel chromatography using a ethyl acetate/hexanes gradient (0% to 75% ethyl acetate) to give 1.16 g (62%) of the subtitle compound. MS calculated for C17H19NS+H 270, observed 270.
