反应详情

To a solution of 1-(2,3-difluorophenyl)-2-fluoroethanone (18.9 g, 109 mmol) in THF (400 mL) was added (R)-(+)-2-methyl-2-propanesulfinamide (26.3 g, 217 mmol) followed by tetraisopropoxytitanium (93 g, 326 mmol). The reaction was heated to reflux for 2 h. The mixture was allowed to cool to room temperature and then treated with brine (400 ml). The resulted suspension was stirred for 15 min and filtered through a pad of celite. The filter cake was washed with EtOAc. The filtrate was extracted with EtOAc (2×). The organic extracts were washed with brine, dried over Na2SO4 and filtered. The filtrate was concentrated and purified by silica gel column (0-20% EtOAc/hexane) to afford (R,E)-N-(1-(2,3-difluorophenyl)-2-fluoroethylidene)-2-methylpropane-2-sulfinamide (12.3 g, 44.4 mmol, 40.9% yield) as yellow oil, MS m/z=278.0 [M+H]+. calculated for C12H14F3NOS: 277.3

1. temperatureThe reaction was heated
2. temperatureto reflux for 2 h
3. filtrationfiltered through a pad of celite
4. washThe filter cake was washed with EtOAc
5. extractionThe filtrate was extracted with EtOAc (2×)
6. washThe organic extracts were washed with brine
7. dry with materialdried over Na2SO4
8. filtrationfiltered
9. concentrationThe filtrate was concentrated
10. custompurified by silica gel column (0-20% EtOAc/hexane)