反应详情

温度

-78 °C

827 mg of 4-(1-methoxy-1-methyl-ethyl)-benzoic acid methyl ester (3.97 mmol) (prepared as described in example S102) and 1.26 ml allyltrimethylsilane (7.94 mmol) were dissolved in 10 ml DCM and the solution was cooled to −78° C. Then 4.77 ml of a 1 M solution of TiCl4 in DCM were added dropwise. After 30 h the reaction was quenched at −78° C. by addition of methanol. Then water was added and the mixture was extracted 3 times with DCM. The combined extracts were washed with brine, dried with magnesium sulfate, filtered and concentrated. The remaining residue was purified by chromatography (silica gel; cyclohexane/EtOAc 95:5) to give 331 mg (38%) of 4-(1,1-dimethyl-but-3-enyl)-benzoic acid methyl ester as a colorless liquid. 1H NMR (CDCl3, 300 MHz): δ 1.33 (s, 6H), 2.38 (d, J=7 Hz, 2H), 3.90 (s, 3H), 4.91-5.00 (m, 3H), 5.51 (m, 1H), 7.41 (d, J=9 Hz, 1H), 7.97 (d, J=9 Hz, 1H).

1. customAfter 30 h the reaction was quenched at −78° C. by addition of methanol
2. additionThen water was added
3. extractionthe mixture was extracted 3 times with DCM
4. washThe combined extracts were washed with brine
5. dry with materialdried with magnesium sulfate
6. filtrationfiltered
7. concentrationconcentrated
8. customThe remaining residue was purified by chromatography (silica gel; cyclohexane/EtOAc 95:5)