反应详情

A 3-L round-bottomed flask equipped with mechanical stirrer and additional funnel was charged with N-hydroxyphthalimide (68.0 g, 0.416 mol) and tetrahydrofuran (1.2 L) under nitrogen atmosphere. To this solution was added triphenylphosphine (109.2 g, 0.416 mol) and (R)-(2,2-dimethyl-[1,3]dioxolan-4-yl)-methanol (55.0 g, 0.416 mol). The mixture was cooled to 3° C. to 5° C. and diethyl azodicarboxylate (85.2 mL, 0.541 mol) was added dropwise, while keeping the inner temperature below 15° C. The reaction mixture was warmed to ambient temperature, and stirred for 18 hours. The tetrahydrofuran was evaporated under reduced pressure. To the remaining orange solid was added dichloromethane (0.5 L) and the mixture was stirred for 1 hour. The white solid (Ph3PO) was filtered and washed with dichloromethane (0.1 L). The solvent was removed and ethanol (0.5 L) was added to the resulting solid. The mixture was stirred for 2 hours at 3° C. to 5° C. The white solid was filtered, washed with a small amount of cold EtOH and dried in vacuum oven at 40° C. to give (S)-2-(2,2-dimethyl-[1,3]dioxolan-4-ylmethoxy)-isoindole-1,3-dione (112.5 g, 97%) as a white solid: 1H NMR (CDCl3): δ 1.33 (s, 3H), 1.99 (s, 3H), 3.96 (m, 1H), 4.15 (m, 2H), 4.30 (m, 1H), 4.48 (m, 1H), 7.59 (m, 2H), 7.84 (m, 2H); MS (APCI+)=278 (M++1).

1. customA 3-L round-bottomed flask equipped with mechanical stirrer and additional funnel
2. temperatureThe mixture was cooled to 3° C. to 5° C.
3. customthe inner temperature below 15° C
4. customThe tetrahydrofuran was evaporated under reduced pressure
5. additionTo the remaining orange solid was added dichloromethane (0.5 L)
6. stirringthe mixture was stirred for 1 hour
7. filtrationThe white solid (Ph3PO) was filtered
8. washwashed with dichloromethane (0.1 L)
9. customThe solvent was removed
10. additionethanol (0.5 L) was added to the resulting solid
11. stirringThe mixture was stirred for 2 hours at 3° C. to 5° C
12. filtrationThe white solid was filtered
13. washwashed with a small amount of cold EtOH
14. customdried in vacuum oven at 40° C.