反应详情

温度

-50 °C

To a suspension of magnesium turnings (17 g) in 50 mL tetrahydrofuran was added dropwise a solution of 5-bromo-1,3-benzodioxole (93.6 g). After complete addition, the mixture was diluted with 250 mL tetrahydrofuran and the resulting mixture was stirred overnight. 13 mL of the solution (0.78M) was transferred to a round bottom flask containing copper (I) iodide (0.12 g). The resulting mixture was cooled to -50 ° C. and a solution of (S)-(-)-propylene oxide in 3 mL tetrahydrofuran was slowly added then stirred 10 min. The mixture was diluted with ether. The isolated organic phase was washed with water and brine. The aqueous wash was extracted with ether (2×) and the combined organic solutions were dried over magnesium sulfate, filtered and concentrated. The residue was purified by silica gel chromatography (50% ether in pentane) to give 1.66 g of the desired product (91%). Chiral HPLC analysis indicated that the optical purity of the material was 98.3%.

1. additionAfter complete addition
2. stirringthen stirred 10 min
3. washThe isolated organic phase was washed with water and brine
4. washThe aqueous wash
5. extractionwas extracted with ether (2×)
6. dry with materialthe combined organic solutions were dried over magnesium sulfate
7. filtrationfiltered
8. concentrationconcentrated
9. customThe residue was purified by silica gel chromatography (50% ether in pentane)