反应详情

The 2-(4-chlorophenyl)-2-methylpropionaldehyde (5.60 g, 30.7 mmol) and (S)-4-methyl-benzenesulfinic acid amide (5.00 g, 32.2 mmol) were dissolved in 300 mL of DCM and treated with Ti(OEt)4 (32.1 mL, 153 mmol). The mixture was heated to reflux under nitrogen for four hours. The solution was cooled in an ice bath and quenched with the dropwise-addition of 200 mL of water. The resulting precipitate (Ti salts) were removed by filtration through a plug of celite and washed with DCM. The resulting filtrate was separated, and the aqueous was extracted with more DCM. The combined organic was dried over MgSO4, filtered, and concentrated in vacuo. The residue was purified by filtration through a plug of silica gel (hexanes:ethyl acetate, 1:1) to afford the (R)-4-methylbenzenesulfinic acid [2-(4-chlorophenyl)-2-methylpropyliden]-amide as a colorless oil, which solidified upon standing to give a white solid (9.28 g, 95%). 1H NMR (CDCl3, 400 MHz) δ 8.14 (s, 1H), 7.54 (d, J=8.4 Hz, 2H), 7.31 (d, J=8.8 Hz, 2H), 7.27 (d, J=8.8 Hz, 2H), 7.14 (m, 2H), 2.42 (s, 3H), 1.52 (s, 3H), 1.47 (s, 3H).

1. temperatureThe mixture was heated
2. temperatureto reflux under nitrogen for four hours
3. temperatureThe solution was cooled in an ice bath
4. customquenched with the dropwise-addition of 200 mL of water
5. customThe resulting precipitate (Ti salts) were removed by filtration through a plug of celite
6. washwashed with DCM
7. customThe resulting filtrate was separated
8. extractionthe aqueous was extracted with more DCM
9. dry with materialThe combined organic was dried over MgSO4
10. filtrationfiltered
11. concentrationconcentrated in vacuo
12. filtrationThe residue was purified by filtration through a plug of silica gel (hexanes:ethyl acetate, 1:1)