Allyl bromide → 2-(4-Methoxy-benzoylamino)-pent-4-enoic acid ethyl ester

反応式

[CH2:1]([O:3][C:4](=[O:17])[CH2:5][NH:6][C:7](=[O:16])[C:8]1[CH:13]=[CH:12][C:11]([O:14][CH3:15])=[CH:10][CH:9]=1)[CH3:2].C[Si](C)(C)[N-][Si](C)(C)C.[Li+].[CH2:28](Br)[CH:29]=[CH2:30]>C1COCC1>[CH2:1]([O:3][C:4](=[O:17])[CH:5]([NH:6][C:7](=[O:16])[C:8]1[CH:9]=[CH:10][C:11]([O:14][CH3:15])=[CH:12][CH:13]=1)[CH2:30][CH:29]=[CH2:28])[CH3:2]

参加物

実験手順

A solution of 11.7 g of (4-methoxy-benzoylamino)-acetic acid ethyl ester (49.6 mmol) in 250 ml of abs. THF was cooled down to −78° and treated with 2.1 eq. of lithium hexamethyldisilazide (104 ml 1M[hexane]). After stirring for 30 min., 1.1 eq. of allyl bromide (4.62 ml) was added neat via syringe and the reaction mixture kept for 15 min. at −78° and for 30 min. at 0°. Pouring onto crashed ice, twofold extraction with AcOEt, twice washing with water, drying over natrium sulfate and evaporation of the solvents, followed by flash chromatography (SiO2, hexane/AcOEt=85/15) afforded 10.56 g of the title compound as off-white solid of mp. 76-78°, besides of 2.74 g of dialkylated product as yellowish oil.