反应详情

温度

-78 °C

In a Fischer-Porter tube, a mixture of 19-2 (10.2 g, 42 mmol) and DME (150 mL) was sequentially, treated with H2SO4 (6.4 mL, 0.12 mol), cooled to -78° C., and then condensed with isobutylene (75 mL). The cooling bath was removed. After 2 h, ice/water (250 mL) was added followed by washing with ether (2×). The aqueous phase was basified with aq 6N NaOH, saturated with NaCl, and extracted with EtOAc (3×). The combined extracts were washed with brine, dried (MgSO4), and concentrated to give a white solid. This was dissolved in CHCl3 then treated with 1N HCl/ether (22 mL) then concentrated to give 19-2a as a glossy yellow solid.

1. customThe cooling bath was removed
2. additionice/water (250 mL) was added
3. washby washing with ether (2×)
4. extractionextracted with EtOAc (3×)
5. washThe combined extracts were washed with brine
6. dry with materialdried (MgSO4)
7. concentrationconcentrated
8. customto give a white solid
9. concentrationthen concentrated