反应详情

A 90.31 g (0.37 mol) portion of ethyl 1-ethoxycarbonyl-β-hydroxy-β-methyl-cyclopropanepropanoate was dissolved in 182 ml of pyridine to which was subsequently added dropwise thionyl chloride at -10° C. to -5° C. After completion of the dropwise addition, this was stirred at the same temperature for 3 hours. After completion of the reaction, the reaction solution was poured into 1 liter of ice water and extracted with dichloromethane (300 ml×3). The organic layers were combined, washed with 1N hydrochloric acid (1 liter×1) and saturated brine (1 liter×1) in that order and then dried on anhydrous sodium sulfate. To the resulting dichloromethane solution was added dropwise 58 ml of 1,8-diazabicyclo[5,4,0]-7-undecene at 0° C., followed by 18 hours of stirring at room temperature. After completion of the reaction, the reaction solution was washed with 1N hydrochloric acid (1 liter×1) and saturated brine (1 liter×1) in that order, and then dried over anhydrous sodium sulfate. After evaporation of the solvent, the resulting residue was applied to a silica gel column chromatography to yield 56.57 g (68%) of the title compound as an oily substance from the eluate of n-hexane:ethyl acetate=9:1.

1. additionAfter completion of the dropwise addition
2. customAfter completion of the reaction
3. extractionextracted with dichloromethane (300 ml×3)
4. washwashed with 1N hydrochloric acid (1 liter×1) and saturated brine (1 liter×1) in that order
5. dry with materialdried on anhydrous sodium sulfate
6. additionTo the resulting dichloromethane solution was added dropwise 58 ml of 1,8-diazabicyclo[5,4,0]-7-undecene at 0° C.
7. waitfollowed by 18 hours
8. stirringof stirring at room temperature
9. customAfter completion of the reaction
10. washthe reaction solution was washed with 1N hydrochloric acid (1 liter×1) and saturated brine (1 liter×1) in that order
11. dry with materialdried over anhydrous sodium sulfate
12. customAfter evaporation of the solvent