Ethyl Acetoacetate → Ethyl 2-acetyl-5,5-dimethyl-4-oxohexanoate

反応式

[C:1]([O:7][CH2:8][CH3:9])(=[O:6])[CH2:2][C:3]([CH3:5])=[O:4].[H-].[Na+].Br[CH2:13][C:14](=[O:19])[C:15]([CH3:18])([CH3:17])[CH3:16]>C1(C)C=CC=CC=1>[C:3]([CH:2]([CH2:13][C:14](=[O:19])[C:15]([CH3:18])([CH3:17])[CH3:16])[C:1]([O:7][CH2:8][CH3:9])=[O:6])(=[O:4])[CH3:5]

参加物

実験手順

Ethyl acetoacetate (1 g, 7.68 mmol) was added dropwise to a suspension of NaH (60% in mineral oil, 338 mg, 8.45 mmol) in toluene (20 mL). The resulting suspension was stirred at rt for 10 min, then treated with 1-bromopinacolone (1.3 g, 7.32 mmol). The mixture was immersed in a 75° C. oil bath, and stirred under Ar for 1 h. The reaction was cooled to rt, diluted with toluene and washed with H2O (2×50 mL). The organic layer was dried over Na2SO4, filtered and concentrated in vacuo to afford crude ethyl 2-acetyl-5,5-dimethyl-4-oxo-hexanoate (1.46 g) which was not purified: 1H NMR (CDCl3, chemical shifts in ppm relative to TMS): 1.166 (s, 9H), 1.277 (t, 3H, J=7.1 Hz), 2.368 (s, 3H), 3.000 (dd, 1H, J=5.8 Hz, J=18.4 Hz), 3.231 (dd, 1H, J=8.2 Hz, J=18.4 Hz), 4.010 (dd, 1H, J=5.8 Hz, J=8.2 Hz), 4.191 (q, 2H, J=7.1 Hz); Field Desorption Mass Spectrometry: m/z 229 (M+1).