Benzene → 1210410-44-8
反応式
P(Br)(Br)[Br:2].[CH:5]1[CH:10]=[CH:9][CH:8]=CC=1.[C:11]([OH:15])([CH3:14])([CH3:13])[CH3:12].O.C[O:18][C:19](C)(C)C>>[Br:2][CH2:5][CH2:10][CH:9]([CH3:8])[C:19]([O:15][C:11]([CH3:14])([CH3:13])[CH3:12])=[O:18]P(Br)(Br)[Br:2].[CH:5]1[CH:10]=[CH:9][CH:8]=CC=1.[C:11]([OH:15])([CH3:14])([CH3:13])[CH3:12].O.C[O:18][C:19](C)(C)C>>[Br:2][CH2:5][CH2:10][CH:9]([CH3:8])[C:19]([O:15][C:11]([CH3:14])([CH3:13])[CH3:12])=[O:18]A mixture of α-methylbutyro-γ-lactone (86.5 g, 0.864 mol) and phosphorus tribromide (PBr3) (86 mL, 0.912 mol) was stirred at 150 to 160° C. for 3 hours under argon. The mixture was cooled to ambient temperature and anhydrous benzene (400 mL) was added. The resulting mixture was heated to reflux for 5 minutes and cooled to ambient temperature. The supernatant of the mixture was carefully transferred to a dry addition funnel with the aid of additional anhydrous benzene (40 mL). The solution in the addition funnel was added quickly to tert-butanol (t-BuOH) (320 g, 4.32 mol) with rapid stirring, while maintaining the internal temperature at 15 to 30° C. by means of a room temperature water bath. After complete addition of the solution to t-BuOH, the resulting mixture was stirred for 30 minutes at ambient temperature, and was then poured into a mixture of water, tert-butyl methyl ether (TBME) and ice. The organic layer was separated, washed with ice cold water, and then washed multiple times with saturated aqueous sodium bicarbonate until the pH of the aqueous layer was 8 to 9. The organic layer was then washed with brine, dried over sodium sulfate, and concentrated to dryness. The residue was applied to a silica gel column and eluted with ethyl acetate (0 to 5%) in hexane. Appropriate fractions were combined and concentrated to afford 1i as a clear oil (58 g, 28% yield). 1H NMR (CDCl3, δ): 1.17 (d), 1.48 (s), 1.90 (m), 2.23 (m), 2.59 (m), and 3.44 (m) ppm; 13C NMR (CDCl3, 8): 17.0, 28.2, 31.2, 36.5, 39.1, 80.6, and 175.1 ppm; MS (TOF) ESI+: [M+Na]+, 259.01, 261.02 Da.
読み込み中…
