反应详情

To a solution of 3-ethoxy-2,2-dimethyl-3-oxopropionic acid (30.78 mmol) in anhydrous CH2Cl2 (20 mL) was added portionwise CDI (40.02 mmol). The reaction mixture was stirred at room temperature during 30 minutes. This solution was added dropwise at −40° C.<T<−30° C. to a solution of 2-mercaptoethanol (41.21 mmol) in anhydrous CH2Cl2 (60 mL). The mixture was stirred at −40° C.<T<−30° C. during 2 hours. The reaction mixture was washed with ice-cold water (×3), dried through a phase separator and evaporated in vacuo while keeping the crude mixture below 25° C. The crude was purified by chromatography on a silica gel column (eluent: petroleum ether/EtOAc 95/5 to 50/50) to give the expected compound as a colorless oil in 30% yield. 1H NMR (DMSO-d6, 400 MHz) δ (ppm) 1.15 (t, J=7.05 Hz, 3H), 1.38 (s, 6H), 2.94 (t, J=6.59 Hz, 2H), 3.43-3.48 (m, 2H), 4.10 (q, J=7.04 Hz, 2H), 4.96 (t, J=5.44 Hz, 1H); MS (ESI) m/z=243 (MNa+).

1. stirringThe mixture was stirred at −40° C.<T<−30° C. during 2 hours
2. washThe reaction mixture was washed with ice-cold water (×3)
3. customdried through a phase separator
4. customevaporated in vacuo
5. customthe crude mixture below 25° C
6. customThe crude was purified by chromatography on a silica gel column (eluent: petroleum ether/EtOAc 95/5 to 50/50)