反応 #81842

反応方程式

n-butyl lithium

3-(1,3-Dioxan-2-yl)-1-(2-pyridyl)-1-propene

[2-(1,3-dioxan-2-yl)ethyl]triphenylphosphonium bromide

2-pyridinecarboxaldehyde

→

E-3-(1,3-dioxan-2-yl)-1-(2-pyridyl)-1 -propene

Z-3-(1,3-dioxan-2-yl)-1-(2-pyridyl)-1-propene

溶媒

water

THF

反応条件

後処理

1. 1
   workup.STIRRINGto stir at room temperature for 1 h
2. 2
   その他partitioned with ether
3. 3
   乾燥extracts were dried over MgSO4
4. 4
   濃縮concentrated
5. 5
   洗浄Flash chromatography (elution with 3:1 hexane:ethyl acetate)

実験手順

(E and Z)-3-(1,3-Dioxan-2-yl)-1-(2-pyridyl)-1-propene (148 and 149). To a suspension of 4.6 g (10.2 mmol) of [2-(1,3-dioxan-2-yl)ethyl]triphenylphosphonium bromide (Aldrich Chemical Co.) in 50 mL of THF at 0° C. was added 6.4 mL (10.2 mmol) of n-butyl lithium (1.6M in hexanes) and the resulting red solution was allowed to stir at 0° C. for 0.5 h. To this solution was added 880 μL (9.3 mmol) of 2-pyridinecarboxaldehyde (Aldrich Chemical Co.). The reaction mixture was allowed to stir at room temperature for 1 h and was then poured into water and partitioned with ether. The combined either extracts were dried over MgSO4 and concentrated. Flash chromatography (elution with 3:1 hexane:ethyl acetate) gave 0.43 g of E-3-(1,3-dioxan-2-yl)-1-(2-pyridyl)-1 -propene (148) and 1.12 g of Z-3-(1,3-dioxan-2-yl)-1-(2-pyridyl)-1-propene (149). 1H NMRs consistent with structures.

出典