反应详情

In a 1 L round button flask, titanium tetrachloride (17.83 mmoles; 1.96 mL; 3.38 g) was dissolved in dichloromethane (70 mL; 1.092 moles; 92.75 g) at room temperature. Then titanium tetra(isopropoxide) (17.83 mmoles; 5.28 mL; 5.07 g) dissolved in dichloromethane (70 mL; 1.092 moles; 92.75 g) was added dropwise at room temperature. After a 1 hour stirring period, ethyl glyoxalate (1.1 equiv; 39.24 mmoles; 3.55 mL; 4.0 g) free of toluene, dissolved in dichloromethane (8.75 mL; 136.5 mmoles; 11.59 g) was added dropwise over 30 min at room temperature. After 15 min., 2,3-dihydrofuran (2.5 g; 1.000 equiv; 35.67 mmoles; 2.70 mL) dissolved dichloromethane (17.5 mL; 273.0 mmoles; 23.19 g) was added over 30 min. at room temperature. After a 3 hours stirring period, isopropyl alcohol (10 equiv; 356.7 mmoles; 27.26 mL; 21.44 g) was added dropwise. After 3 hours, the mixture of potassium carbonate (1.75 g; 12.66 mmoles) and Rochelle salt (17.5 g; 83.25 mmoles) dissolved in water (175 mL; 9.72 moles; 175 g) was added to the reaction mixture. After stirring over weekend, the two layers were separated and the organic layer was washed with (2×100 mL) of water (200 mL; 11.10 moles; 200.0 g). The organic solvent was evaporated over reduced pressure to afford the desired product (7.48 g; GC: 92 area %).

1. additionwas added dropwise at room temperature
2. additionwas added dropwise over 30 min at room temperature
3. waitAfter 15 min.
4. additionwas added over 30 min. at room temperature
5. stirringAfter a 3 hours stirring period
6. waitAfter 3 hours
7. additionwas added to the reaction mixture
8. stirringAfter stirring over weekend
9. customthe two layers were separated
10. customThe organic solvent was evaporated over reduced pressure