Diethyl Ether → 5,7-Difluoro-1-(triisopropylsilyl)-1H-indole

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Reaction Conditions

Reaction Steps

N-butyl lithium (2.7 ml, 2.5 M, 6.9 mmol) was added to 10 mL dry THF at −70° C. 5,7-difluoro-1H-indole (1.0 g, 6.5 mmol) in 5 mL THF was added in portions to the this solution and the mixture was stirred for 30 min at −75° C. Triisopropylchlorosilane (1.5 mL, 1.3 g, 6.9 mmol) was added, stirring was continued for 1 h at −75° C. and then the mixture was allowed to warm to −5° C. over 2 h. After treatment with 5 mL sat. NH4Cl, the mixture was mixed with 30 mL ether and the organic phase was washed with 5 mL sat. NaCl, dried (Na2SO4) and evaporated. The product was purified by flash chromatography (SiO2; hexanes) to provide the title compound as a clear oil (1.5 g; 74%): 1H NMR (400 MHz, CDCl3) δ 7.35 (d, J=3.1 Hz, 1H), 7.07 (dd, J=8.7, 2.3 Hz, 1H), 6.69 (m, 1H), 6.59 (t, J=3.1 Hz, 1H), 1.67 (m, 3H), 1.13 (d, J=7.6 Hz, 18H). 19F NMR (376 MHz, CDCl3) δ −120.64, −120.65, −122.49, −122.49. EIMS m/z 309.

Provenance & Evidence