Tetrahydrofuran → (S)-2-(3-Ethoxycarbonylallyl)-piperazine-1,4-dicarboxylic acid di-tert-butyl ester

Reaktionsgleichung

[C:1]([O:5][C:6]([N:8]1[CH2:13][CH2:12][N:11]([C:14]([O:16][C:17]([CH3:20])([CH3:19])[CH3:18])=[O:15])[CH2:10][C@@H:9]1CC=O)=[O:7])([CH3:4])([CH3:3])[CH3:2].[C:24]([CH:29]=P(C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1)([O:26][CH2:27][CH3:28])=[O:25].[CH2:49]1COC[CH2:50]1>>[C:1]([O:5][C:6]([N:8]1[CH2:13][CH2:12][N:11]([C:14]([O:16][C:17]([CH3:18])([CH3:19])[CH3:20])=[O:15])[CH2:10][C@@H:9]1[CH2:49][CH:50]=[CH:29][C:24]([O:26][CH2:27][CH3:28])=[O:25])=[O:7])([CH3:3])([CH3:4])[CH3:2]

Komponenten

Edukt 3

HCID 8028Tetrahydrofuran

HCID 70670Acetic acid, 2-(triphenylphosphoranylidene)-, ethyl ester

HCID 86604575(S)-2-(2-Oxoethyl)piperazine-1,4-dicarboxylic acid di-tert-butyl ester

Produkt 1

HCID 69212154(S)-2-(3-Ethoxycarbonylallyl)-piperazine-1,4-dicarboxylic acid di-tert-butyl ester

Versuchsvorschrift

Heat a mixture of (S)-2-(2-oxoethyl)-piperazine-1,4-dicarboxylic acid di-tert-butyl ester (1.38 g, 4.21 mmol) and (carbethoxymethylene)triphenylphosphorane (1.87 g, 5.38 mmol) in THF (17 mL) at reflux for 4 h. Concentrate the mixture under reduced pressure and purify by silica gel chromatography eluting with 20% to 50% EtOAc in hexanes. Combine the purified fractions, concentrate under reduced pressure, azeotrope with CH2Cl2/hexanes (1:2) and place under vacuum to give the title compound: yellow tar (0.961 g), mass spectrum (m/e): 416.09(M+NH4).