| prepare | 100mL round bottom flask with 1,2:4,5-di-o-isopropylidene-β-d-2, 3-diketone -2,6-pyranose 13g, acetic acid 17.5g, water 4.3ml, zinc chloride 170mg, reaction at room temperature for 15 hours, TLC point plate monitoring until the raw material reaction is complete. Then continue to add 64.9g acetic anhydride, continue to stir for 15 hours, TLC point plate monitoring until the third intermediate diol reaction is complete. Dissolve the reaction solution with 100mL of ethyl acetate and pass through a 2cm silica gel column, collect and spin dry to obtain a colorless oily liquid, add 10mL of water and stir for 30min, and then spin dry to obtain a large amount of white solid, namely Shi Yi'an epoxidized chiral ketone catalyst hydrate crude product. Then 20ml of ether was added and stirred for 20min, and 16.7g of white solid hydrate of pure Shi-an epoxidized chiral ketone catalyst was obtained by suction filtration with 90% yield. |
