反应详情

Dry Mg (0.58 g) under dry N2 in a flask is covered with THF (5 ml) and a crystal of I2 added. 5 ml of a solution of 4-bromobenzaldehyde ethylene acetal (5.0 g) in THF (25 ml) is added and kept until it becomes warm, when it is cooled to 15°, and the remainder of the acetal added over 15 min, then stirred for an additional 1 hour. A mixture of ground lithium chloride (0.35 g) and copper (I) chloride (0.70 g) dissolved in THF is prepared, treated with 1,2-dichloropropene (CH2Cl.CCl=CH2) (4.5 g) and cooled to -20°. The above Grignard solution (under moisture excluding conditions) is then added to this solution during 5 min, and allowed to warm to 20° with stirring for 16 hours. Saturated aqueous ammonium chloride is added and the organic layer evaporated under reduced pressure to a small residue, which is dissolved in THF (100 ml), cooled to -100°, treated with 3N HCl (50 ml), then stirred at 20° for 1 hour. The product is partitioned between ether and water, and the ether layer washed with NaHCO3, H2O NaCl, dried (MgSO4) and the residue chromatographed on florisil. The fraction eluted by 15% ether in petrol is collected and purified by preparative HPLC. Yield 0.50 g (13%) nD20 1.5571.

1. temperaturebecomes warm
2. temperaturewhen it is cooled to 15°
3. customis prepared
4. temperaturecooled to -20°
5. additionThe above Grignard solution (under moisture excluding conditions) is then added to this solution during 5 min
6. temperatureto warm to 20°
7. stirringwith stirring for 16 hours
8. customthe organic layer evaporated under reduced pressure to a small residue, which
9. dissolutionis dissolved in THF (100 ml)
10. temperaturecooled to -100°
11. additiontreated with 3N HCl (50 ml)
12. stirringstirred at 20° for 1 hour
13. customThe product is partitioned between ether and water
14. washthe ether layer washed with NaHCO3, H2O NaCl
15. dry with materialdried (MgSO4)
16. customthe residue chromatographed on florisil
17. washThe fraction eluted by 15% ether in petrol
18. customis collected
19. custompurified by preparative HPLC