1-(Bromomethyl)-2,4-difluorobenzene → (4s,7r)-2-(2-Chloro-4-fluoro-phenyl)-1-(2,4-difluoro-benzyl)-7,8,8-trimethyl-1,2,4,5,6,7-hexahydro-4,7-methano-indazol-3-one

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Reaction Conditions

Reaction Steps

A mixture of (4S,7R)-2-(2-chloro-4-fluoro-phenyl)-7,8,8-trimethyl-1,2,4,5,6,7-hexahydro-4,7-methano-indazol-3-one (Intermediate 21; 200 mg, 0.62 mmol), tetrabutylammonium iodide (229 mg, 0.62 mmol) and 2,4-difluorobenzyl bromide (320 μL, 2.5 mmol) in dimethylformamide (4 mL) was heated at 80° C. overnight. The solvent was evaporated and dichloromethane (50 mL) was added. The solution was washed with water (2×20 mL), saturated aqueous sodium thiosulfate (20 mL), and brine (20 mL), dried (magnesium sulfate), filtered, concentrated and purified by chromatography, eluting with 60-70% ethyl acetate/petroleum ether, to give (4S,7R)-2-(2-chloro-4-fluoro-phenyl)-1-(2,4-difluoro-benzyl)-7,8,8-trimethyl-1,2,4,5,6,7-hexahydro-4,7-methano-indazol-3-one (182 mg, 68%) as an off-white solid. APCI(+)-MS (M+H) 447.

Provenance & Evidence