Ethyl chrysanthemate → Chrysanthemic Acid
Reaktionsgleichung
CC[O:3][C:4]([CH:6]1[C:8]([CH3:10])([CH3:9])[CH:7]1[CH:11]=[C:12]([CH3:14])[CH3:13])=[O:5].B(Br)(Br)Br>O1CCOCC1>[CH3:13][C:12]([CH3:14])=[CH:11][CH:7]1[C:8]([CH3:9])([CH3:10])[CH:6]1[C:4]([OH:5])=[O:3]Komponenten
4
Reagenzien, Katalysatoren, Lösungsmittel 1
Reaktionsbedingungen
- Temperatur
- 15 °C
Versuchsvorschrift
In a 50 ml flask, there were charged ethyl chrysanthemate (composition: (+)-cis, 2.5%; (-)-cis, 16.8%; (+)-trans, 12.3%; (-)-trans, 68.4%) (2.0 g) and dioxane (18.0 g) under nitrogen. Boron tribromide (0.26 g) was added thereto at 15° C. with stirring and stirred for 4 hours. Then a small amount of the reaction mixture was hydrolyzed to obtain chrysanthemic acid. The composition of the optical isomers in the product was determined by the same method as described in EXAMPLE 1. The result was as follows: (+)-cis, 2.4%; (-)-cis, 2.6%; (+)-trans, 46.2%; (-)-trans, 48.8%.