3-丁烯酯的制备.pdf

Preparation of But-3-enoate Esters But-2E-enoyl chloride. A 250 mL round-bottom flasked was charged with crotonic acid (100.0 g, 1.16 mol, 1.0 eq.). An addition funnel containing thionyl chloride (84.3 mL, 1.16 mol, 1.0 eq) was attached to the flask, then the whole apparatus was flushed with nitrogen. The thionyl chloride was added to the crotonic acid at a rate of roughly 3-5 drops per second; the whole addition took place over 1 hour, during which time the escape of the evolved gas cooled the solution sufficiently to control the rate of reaction. After the addition was complete, the mixture was heated to 80 °C until no further gas evolution took place (roughly 2 hours). The light orange-colored solution was then allowed to cool to room temperature. The product was directly distilled from the reaction flask (oil bath temperature = 200 °C, head temperature = 115-120 °C, 1 atm.) to obtain 107.9 g (89%) but-2E-enoyl chloride. 1H NMR (400 MHz, CDCl ): δ 7.25 (dq, J = 15.1, 6.9 Hz, 1H), 6.10 (d, J = 15.1 Hz, 1H), 2.00 (d, J = 6.8 Hz, 3H). 13C NMR 3 (101 MHz, CDCl ): δ 165.6, 152.6, 127.8, 18.3 . 3 Methyl but-3-enoate (1). A 500 mL round-bottom flask charged with methanol (12.6 mL, 310 mmol, 1.5 eq.), 275 mL n-pentane, and triethylamine (28.8 mL, 207 mmol, 1.0 eq.) was cooled to 0 °C. Crotonoyl chloride (19.8 mL, 207 mmol, 1.0 eq.) was then added dropwise over 20 minutes. The solution, which instantly formed a white-colored precipitate, was allowed to warm to room temperature after the addition. After stirring for 1 hour, 10 mL of a saturated aqueous NaHCO3 solution was added to the reaction mixture, followed by 50 mL deionized H O. The reaction mixture was then poured into a