Example 1
To a solution of the SM (137 g, 0.34 mol) in THF (1.3 L) at 0 C was slowly added BH3-SMe2 (97 mL, 1.02 mol). The reaction mixture was allowed to warm to RT then was heated at reflux for 15 h. The mixture was then cooled in an ice bath, and MeOH (40 mL) was added dropwise. The mixture was stirred at RT for 20 min. Aq 2M NaOH (1.2 L) was added and the layers were separated. The aq layer was extracted with EtOAc. The combined organics were washed with brine, dried (MgSO4), and concentrated. The resulting material was purified by passing through a short plug of silica gel (eluting with 30% EtOAc/heptane) to provide the product as a colorless solid (61.4 g, 50%). Impure material from the first purification was purified again via the same procedure to provide a second batch of product (22 g, 18%) as a colorless solid. [combined yield: 83.4 g, 68%]
[Patent Reference: WO2012069948, page 55, (3.9 MB)]