反应详情

A 3-neck, 5-L round-bottom flask equipped with a vacuum distillation head, a thermometer, and a magnetic stir bar was charged with dimethyl fluoromalonate (339 g assayed at 83% purity by VPC, 1.88 mol), benzyl alcohol (935 mL, 9.04 mol), toluene (846 mL), and p-toluenesulfonic acid monohydrate (21.5 g, 0.113 mol). The mixture was heated under vacuum (10-15 inches of Hg) until all of the toluene had distilled, then at 28-29 inches of Hg (water aspirator vacuum), the reaction temperature being maintained at 100° to 115° C. The progress of the reaction was monitored by 19F NMR. After a total of 7 hours, the heat was removed, and the mixture was allowed to cool, with continued stirring. When the temperature had lowered to 75° C., isopropanol (450 mL) was added. When the temperature had lowered to 55° C., hexane (1 L) was added. The product crystallized out and the mixture was placed in the freezer overnight. The product was filtered, washed with hexane (2×1 L), sucked dry, and dried overnight in vacuo. The yield was 452 g (96% pure by weight). A second crop of 29 g was obtained from the combined filtrates and washings, for a total yield of 81%.

1. distillationhad distilled
2. temperatureat 28-29 inches of Hg (water aspirator vacuum), the reaction temperature being maintained at 100° to 115° C
3. customAfter a total of 7 hours, the heat was removed
4. temperatureto cool, with continued stirring
5. customhad lowered to 75° C.
6. additionisopropanol (450 mL) was added
7. customhad lowered to 55° C.
8. additionhexane (1 L) was added
9. customThe product crystallized out
10. customwas placed in the freezer overnight
11. filtrationThe product was filtered
12. washwashed with hexane (2×1 L)
13. customsucked dry
14. customdried overnight in vacuo
15. customA second crop of 29 g was obtained from the combined filtrates and washings, for a total yield of 81%