反应详情

To magnesium turnings (30.2 g, 1.24 mol) in THF (30 mL) is added 1,2-dibromoethane (0.7 mL) followed by dropwise addition, over 1 h, of 4-bromotrifluoromethylbenzene (200 g, 0.89 mol) dissolved in THF (700 mL). The reaction is heated occasionally to maintain a gentle reflux and is stirred 45 min after the addition is complete. The dark reaction mixture is then cooled in an ice bath and acetone (103 g, 1.78 mol) added dropwise. After stirring an additional 1.5 h the reaction is carefully quenched with aqueous saturated NaHSO4, ethyl acetate added, the organics dried over MgSO4, concentrated and purified by silica gel chromatography (9:1 to 3:2, hexane to ethyl acetate) to give 4-trifluoromethyl-α,α-dimethylbenzyl alcohol of sufficient purity to carry to the next step; yield: 114 g (63%).

1. temperatureThe reaction is heated occasionally
2. temperatureto maintain
3. temperaturea gentle reflux
4. additionafter the addition
5. customThe dark reaction mixture
6. temperatureis then cooled in an ice bath
7. stirringAfter stirring an additional 1.5 h the reaction
8. customis carefully quenched with aqueous saturated NaHSO4, ethyl acetate
9. additionadded
10. dry with materialthe organics dried over MgSO4
11. concentrationconcentrated
12. custompurified by silica gel chromatography (9:1 to 3:2, hexane to ethyl acetate)