Tetrahydrofuran → 5-(tert-Butyldimethylsilyloxymethyl)-2-(3-methyl-butyryl)-pyridine
Reaktionsgleichung
Br[C:2]1[CH:7]=[CH:6][C:5]([CH2:8][O:9][Si:10]([C:13]([CH3:16])([CH3:15])[CH3:14])([CH3:12])[CH3:11])=[CH:4][N:3]=1.[Li][CH2:18]CCC.[CH2:22]1[CH2:26][O:25][CH2:24][CH2:23]1>>[Si:10]([O:9][CH2:8][C:5]1[CH:6]=[CH:7][C:2]([C:26](=[O:25])[CH2:22][CH:23]([CH3:18])[CH3:24])=[N:3][CH:4]=1)([C:13]([CH3:16])([CH3:15])[CH3:14])([CH3:12])[CH3:11]Komponenten
4
Reaktionsbedingungen
- Temperatur
- -78 °C
Versuchsvorschrift
Dissolve 2-bromo-5-(tert-butyldimethylsilyloxymethyl)pyridine (1.99 g, 6.583 mmol, prepared by following the procedure described in J. Org. Chem. 2004, 69, 250-262) in anhydrous THF (20 mL). Cool the solution to −78° C., add n-BuLi (4.32 mL, 6.912 mmol, 1.6M solution in hexane) and stir at this temperature for 40 min. Add slowly a solution of N-methoxy-AT-methyl-3-methyl-butyramide (0.955 g, 6.583 mmol) in anhydrous THF (5 mL). Stir the mixture for 2 h at −78° C. and then allow the mixture to warm to room temperature. Add brine and extract the aqueous layer twice with EtOAc. Dry the combined organic extracts over Na2SO4, filter and concentrate in vacuo. Purify the crude mixture by chromatography on silica gel eluting with hexane and hexane/EtOAc (19:1) to give the desired intermediate as yellow oil (890 mg, 44%). GC-MS m/z: 307 (M+).