(R)-2,2-dimethyl-1,3-dioxolane-4-carbaldehyde → 2,2-Dimethyl-alpha-2-propenyl-1,3-dioxolane-4-methanol
反応式
[CH2:1]([Mg]Br)[CH:2]=[CH2:3].[CH3:6][C:7]1([CH3:14])[O:11][C@@H:10]([CH:12]=[O:13])[CH2:9][O:8]1>O1CCCC1>[CH3:6][C:7]1([CH3:14])[O:11][CH:10]([CH:12]([CH2:3][CH:2]=[CH2:1])[OH:13])[CH2:9][O:8]1参加物
4
反応条件
- 温度
- -78 °C
実験手順
To a stirring -78° C. solution, under argon, of 556 ml of 1M allylmagnesium bromide is added, dropwise over 20 minutes, a solution of 36.4 g of product from Example 330 in 17 ml of tetrahydrofuran. The reaction mixture is stirred at -78° C. for 2 hours. Thin layer chromatography indicates the presence of starting material. An additional 280 ml of 1M allylmagnesium bromide is added and the reaction is stirred overnight at -78° C. The reaction is quenched with dropwise addition of saturated ammonium chloride, filtered through diatomaceous earth and washed with diethyl ether, ethyl acetate and 20% isopropyl alcohol/chloroform. The combined extracts are washed with saturated sodium chloride, dried and concentrated in vacuo to give after Kugelrohr distillation at 85° C., 38.25 g of the desired product.