Diethyl Ether → Diethyl 2-pent-4-enylpropanedioate

Participants

Reaction Steps

7.05 g of sodium were dissolved in a solution of 49 g of diethyl malonate in 175 ml of ethanol. The still warm solution (50° C.) was treated dropwise within 15 minutes with 45.6 g of 5-bromo-1-pentene and the mixture was heated to boiling for 2 hours. After cooling the reaction mixture was poured into 500 ml of diethyl ether and 300 ml of semi-saturated sodium chloride solution. The aqueous phase was separated and back-extracted twice with 200 ml of diethyl ether each time. The organic phases were washed twice with 150 ml of semi-saturated sodium chloride solution each time, dried over sodium sulphate, filtered and concentrated. Chromatographic separation of the resulting, yellow liquid (55.2 g) on silica gel with hexane/ethyl acetate (vol. 95:5) gave 33.2 g of diethyl (4-pentenyl)-malonate as a colourless liquid.

Provenance & Evidence