Example 1
To a mixture of the SM (200 g, 0.995 mol) in dry THF (1.7 L) at -70 C was added dropwise a solution of nBuLi in hexane (438 mL, 1.09 mol). After stirring at -70 C for 1 h, dry DMF (76.3 g, 1.04 mol) was added dropwise at -70 C. The reaction mixture was stirred at -70 C for 1 h, after which time the mixture was poured into aq NH4Cl (1 L) and extracted with EtOAc. The combined organics were washed with brine, dried (Na2SO4), and concentrated to provide the product as a yellow oil. [147 g, 98%]
[Patent Reference: WO2016014463, page 93, (6.7 MB)]