5-bromo-1H-indazole → 2,2,2-trifluoro-1-(1H-indazol-5-yl)-1-(1-methyl-1H-indol-3-yl)ethanol

Participants

Reaction Steps

To a chilled (−78° C.) solution of 1.5 g (7.61 mmol) of 5-bromoindazole in 15 mL ether was added 9.2 mL (23.0 mmol) of a 2.5 M solution of n-butyllithium in hexanes. After 5 minutes, the cold bath was removed and the mixture stirred 6 hours at room temperature. The mixture was cooled to −78° C. and 3.5 g (15.4 mmol) of 2,2,2-trifluoro-1-(1-methyl-1H-indol-3-yl)ethanone in 4 mL of a 1:1 mixture of ether-THF was added. The mixture was stirred overnight while warming to room temperature and was then quenched with aqueous ammonium chloride and extracted with ether. The organic layer was washed with water, brine, and dried over magnesium sulfate. Removal of the volatiles in vacuo provided a residue which was purified by CombiFlash chromatography using 0-90% EtOAc-hexanes (product eluted at 35% EtOAc) to afford 700 mg (26%) of 2,2,2-trifluoro-1-(1H-indazol-5-yl)-1-(1-methyl-1H-indol-3-yl)ethanol as a pale yellow foam.

Provenance & Evidence