Ethyl-2-butenoate

To a stirred solution of 1.5 mmol of LDA in 3.5 mL of a 60 40 mixture of THF/hexane at — 78 °C tinder a nitrogen atmosphere are added 209 mg (1.5 mmol) of l-(l-oxo-2-butenyl)pyrrolidine in 1.5 mL of HMPA. After 30 min 86 mg (0.75 mmol) of ethyl ( )-2-butenoate in 1.5 mL of THF is added and the mixture is stirred for an additional half hour at — 78CC. The mixture is quenched by addition of sat. aq NH4C1. Extraction with diethyl ether is followed by drying over Na2S04, followed by evaporation of the solvent and short path distillation to give the syn-adduct yield 123 mg (65%). 

To a stirred suspension of 2.3 mmol LDA in 20 mL of THF arc added at — 80 X under a nitrogen atmosphere 253 mg (1 mmol) of methyl 2-(2-hydroxy-2,6,6-trimethylbicyclo[3.1.1]hept-3-ylideneamino)propanoate and the mixture is stirred for a further 30 min. After the addition of 114 mg (1 mmol) of ethyl ( )-2-butenoate the mixture is stirred at — 80 °C until the reaction is complete (followed by TLC on silica gel). The mixture is poured into 70 mL of sat. aq NH4C1 and subsequently extracted three times with diethyl ether. The combined ether layers arc dried over Na2S04 and the solvent is evaporated. The crude adduct is purified by chromatography (silica gel. diethyl ether/hexane 66 34) yield 330 mg (90%). 

Hudlicky and Barbieri (178) developed a simple procedure to synthesize the substituted vinyl oxiranes by adding the lithium dienolate of a l-bromo-4-silyloxy-ethyl-2-butenoate to substituted aldehydes. From the vinyl oxiranes formed. 

White wine (Riesling) Ethyl 2-butenoate, ethyl hexanoate, butanoic acid, 3-methylbutanoic acid, methionol (134), 7-undecalactone (135), 4-vinylguaiacol 156... 

C6H9N03 3,5,5-tri methyl-2,4-oxazolidinedione 127-48-0 25.00 1.1467 2 7821 C6H10O2 trans-2-ethyl-2-butenoic acid 1187-13-9 50.00 0.9578 1... 

Problem 26.5 In an example of the Michael condensation, malonic ester reacts. with ethyl 2-butenoate in the presence of sodium ethoxide to yield A, of formula C13H22O6. The sequence of hydrolysis, acidification, and heating converts A into 3-methylpentanedioic acid. What is A, and how is it formed Hint See Sec. 8.20. Check your answer in Sec. 27.7.)... 

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