反应详情

To a solution of (1R)cis 3(2,2-dibromovinyl)-2,2-dimethylcyclopropane carboxylate (0.11 g) in CH2Cl2 (3 ml) cooled to 0° is added successively 4(Z-3-chloroallyl) benzyl alcohol (0.070 g) in CH2Cl2 (2 ml), N,N1 dicyclohexylcarbodiimide (0.076 g) in CH2Cl2 (2 ml), and 4-dimethylamino pyridine (0.010 g). This mixture is stirred for 30 minutes at 0°, then for 16 hours at 20°. The resulting precipitate is filtered off, the filtrate evaporated under reduced pressure and the residue chromatographed on florisil. The fraction eluted by 7% diethyl ether in petroleum ether bp 60°-80° C. ether in petrol is evaporated to a residue of 4(-3-chloroallyl)benzyl (1R)-3(2,2-dibromovinyl)-2,2-dimethylcyclopropane carboxylate (0.15 g) 91% nD20 1.5684.

1. waitfor 16 hours at 20°
2. filtrationThe resulting precipitate is filtered off
3. customthe filtrate evaporated under reduced pressure
4. customthe residue chromatographed on florisil
5. washThe fraction eluted by 7% diethyl ether in petroleum ether bp 60°-80° C. ether in petrol
6. customis evaporated to a residue of 4(-3-chloroallyl)benzyl (1R)-3(2,2-dibromovinyl)-2,2-dimethylcyclopropane carboxylate (0.15 g) 91% nD20 1.5684