反应详情

To a solution of ethyl 7-oxabicyclo[4.1.0]heptane-3-carboxylate (17.8 g) in CH2Cl2 (350 mL) was added 40% HBr solution (120 mL). The biphasic mixture was stirred vigorously for 25 min, then was neutralized with aqueous NaHCO3 solution. The organic layer was collected and dried over MgSO4, then was concentrated in vacuo. The residue was diluted with toluene (120 mL), and para-toluene sulfonic acid (120 mg, 0.6 mmol) was added. The mixture was heated at 128° C. with azeotropic removal of water over 3.5 hours, then was concentrated in vacuo to afford 21 g of a brown residue, which was used in the next reaction without purification.

1. customThe organic layer was collected
2. dry with materialdried over MgSO4
3. concentrationwas concentrated in vacuo
4. additionwas added
5. concentrationwas concentrated in vacuo