Trifluoroacetic acid → (4s,7r)-2-(3,5-Dichloro-phenyl)-7,8,8-trimethyl-1,2,4,5,6,7-hexahydro-4,7-methano-indazol-3-one

Participants

Reaction Conditions

Reaction Steps

Trifluoroacetic acid (15 mL) was added in one portion to a cooled (0° C.) solution of N′-(3,5-dichloro-phenyl)-N′-((1R,4R)-4,7,7-trimethyl-3-oxo-bicyclo[2.2.1]heptane-2-carbonyl)-hydrazinecarboxylic acid tert-butyl ester (˜0.19 mmol) in dichloromethane (15 mL). The mixture was stirred at 0° C. for 5 min and then the cooling bath was removed and the reaction mixture was allowed to warm to room temperature and stir for 4 h. Volatiles were evaporated under reduced pressure and then under high vacuum. Dichloromethane (200 mL) was added. The solution was washed with water (4×125 mL), and brine (100 mL), dried (magnesium sulfate), filtered, evaporated, and dried overnight under high vacuum to give (4S,7R)-2-(3,5-dichloro-phenyl)-7,8,8-trimethyl-1,2,4,5,6,7-hexahydro-4,7-methano-indazol-3-one (7.2 g, 108% of the expected amount). This material was used in subsequent reactions without further purification.

Provenance & Evidence