Tetrahydrofuran → 1-benzyl 2-tert-butyl (2S,4R)-5-oxo-4-[(2E)-3-phenyl-2-propenyl]-1,2-pyrrolidinedicarboxylate
Reaktionsgleichung
[O:1]=[C:2]1[N:6]([C:7]([O:9][CH2:10][C:11]2[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=2)=[O:8])[C@H:5]([C:17]([O:19][C:20]([CH3:23])([CH3:22])[CH3:21])=[O:18])[CH2:4][CH2:3]1.[Li+].C[Si]([N-][Si](C)(C)C)(C)C.[CH2:34]1[CH2:38]O[CH2:36][CH2:35]1>>[O:1]=[C:2]1[N:6]([C:7]([O:9][CH2:10][C:11]2[CH:12]=[CH:13][CH:14]=[CH:15][CH:16]=2)=[O:8])[C@H:5]([C:17]([O:19][C:20]([CH3:23])([CH3:22])[CH3:21])=[O:18])[CH2:4][C@H:3]1[CH2:36]/[CH:35]=[CH:34]/[C:38]1[CH:17]=[CH:5][CH:4]=[CH:3][CH:2]=1Komponenten
4
Reaktionsbedingungen
- Temperatur
- -78 °C
Versuchsvorschrift
To a solution of protected pyroglutamate 8a (1.023 g, 3.20 mmol) in 15 mL THF at −78° C., was added LiHMDS (1M THF, 3.20 mL, 3.20 mmol). The mixture was stirred at −78° C. for 1 h, then a solution of cinnamyl Br in THF (3 mL) was added. The mixture was stirred at −78° C. for 1.25 h, then was quenched with sat. NH4Cl. The mixture was diluted with H2O, then extracted with EtOAc (3×). The organic phase was washed with brine, dried (Na2SO4), and concentrated. The crude product was purified by flash chromatography (15% EtOAc/hexanes) to afford 390 mg (28%) of 8b as a white solid. 1H NMR (300 MHz, CDCl3) δ7.43-7.22 (m, 10H), 6.46 (d, J=15.7, 1H), 6.18-6.06 (m, 1H), 5.33-5.20 (m, 2H), 4.50 (dd, J=9.3, 1.7, 1H), 2.88-2.63 (m, 1H), 2.45-2.33 (m, 1H), 2.24-2.12 (m, 2H), 1.38 (s, 9H); MS (ESI) 436.2 (M+H+).