反应详情

温度

-70 °C

To a solution of 3-ethoxy-4-trifluoromethyl-benzonitrile from step 5 (5.00 g, 23.2 mmol), copper(I) bromide (100 mg, 0.7 mmol), tert.-butyldimethylchlorosilane (4.20 g, 27.9 mmol) in dry THF (30 mL) at −70° C. was drop wise added a 3 M methylmagnesium bromide solution in diethyl ether (13.2 mL, 39.6 mmol). The mixture was stirred at −70° C. for 10 min, then was warmed up to 0° C. and stirring was continued at 0° C. for further 2 h under nitrogen atmosphere. Poured the reaction mixture onto ice and sat. NH4Cl-sol., extracted three times with diethyl ether, washed the combined organic layers with brine, dried over MgSO4. Removal of the solvent in vacuum left a brown oil, which was purified by silica gel column chromatography with heptane/EtOAc 4:1 to give the title compound as a yellow liquid (1.84 g, 34%). MS (EI) 232 [M].

1. customat −70° C.
2. temperaturewas warmed up to 0° C.
3. stirringstirring
4. waitwas continued at 0° C. for further 2 h under nitrogen atmosphere
5. extraction, extracted three times with diethyl ether
6. washwashed the combined organic layers with brine
7. dry with materialdried over MgSO4
8. customRemoval of the solvent in vacuum
9. waitleft a brown oil, which
10. customwas purified by silica gel column chromatography with heptane/EtOAc 4:1