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

35.4 g (221 mmol) of diethyl malonate and 402 mL of toluene were added into a three-necked flask (1 L), and thereafter, 82.7 mL (211 mmol) of a 20% sodium ethoxide ethanol solution was added thereto as a base. The obtained mixture was stirred at room temperature for 0.5 hours, and 21.5 g of trans-1,4-dibromo-2-butene (101 mmol; a reagent manufactured by Sigma-Aldrich) was then added to the reaction solution. The obtained mixture was stirred at room temperature for 22 hours, and 241 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 240 mL of toluene, and organic layers were then gathered. The gathered organic layer was washed with 240 mL of water three times. The resultant was filtrated, while washing the residue with toluene. The obtained filtrate was concentrated at 45° C. under reduced pressure, so as to obtain 23.6 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 21.2 g of 1,1-di-ethoxycarbonyl-2-vinylcyclopropane (yield: 99%).

1. additionwas then added to the reaction solution
2. stirringThe obtained mixture was stirred at room temperature for 22 hours
3. stirringThe mixture was stirred for 1 hour
4. customan organic layer was then separated
5. extractionA water layer was re-extracted with 240 mL of toluene, and organic layers
6. washThe gathered organic layer was washed with 240 mL of water three times
7. filtrationThe resultant was filtrated
8. washwhile washing the residue with toluene
9. concentrationThe obtained filtrate was concentrated at 45° C. under reduced pressure

ORD record

ord-fd99db5d4b944d6ba0317d56d933bc28

Source dataset

uspto-grants-2015_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09061991B2