Diethyl Malonate → Diethyl 2-vinylcyclopropane-1,1-dicarboxylate

80.2 g (501 mmol) of diethyl malonate and 850 mL of toluene were added into a four-necked flask (2 L), and thereafter, 191.7 mL (489 mmol) of a 20% sodium ethoxide ethanol solution was added thereto as a base. The obtained mixture was stirred at room temperature for 1.5 hours, and 51.0 g of trans-1,4-dibromo-2-butene (238 mmol; a reagent manufactured by Aldrich) was then added to the reaction solution. The obtained mixture was stirred at room temperature for 3 hours, and 537 mL of a 1 M sodium hydroxide aqueous solution was then added to the reaction solution. The mixture was stirred for 1 hour, and an organic layer was then separated. A water layer was re-extracted with 173 mL of toluene, and organic layers were then gathered. The gathered organic layer was washed with 86 mL of water twice, and it was then dried over anhydrous sodium sulfate, followed by filtration. The obtained filtrate was concentrated at 45° C. under reduced pressure, so as to obtain 53.3 g of 1,1-di-ethoxycarbonyl-2-vinylcyclopropane in the form of a crude product of a light yellow oily substance. This crude product contained 49.7 g of 1,1-di-ethoxycarbonyl-2-vinylcyclopropane (yield: 98.5%). In addition, it contained no diethyl malonates.

1. additionwas then added to the reaction solution
2. stirringThe obtained mixture was stirred at room temperature for 3 hours
3. stirringThe mixture was stirred for 1 hour
4. customan organic layer was then separated
5. extractionA water layer was re-extracted with 173 mL of toluene, and organic layers
6. washThe gathered organic layer was washed with 86 mL of water twice
7. dry with materialit was then dried over anhydrous sodium sulfate
8. filtrationfollowed by filtration
9. concentrationThe obtained filtrate was concentrated at 45° C. under reduced pressure

ORD record

ord-252ce5b9ad56442b87601b522567f98d

Source dataset

uspto-grants-2015_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09061991B2