Diisopropylamine → Ethyl 3-cyclopropyl-3-(4-trifluoromethylphenyl)propenoate

Participants

Reaction Conditions

Reaction Steps

A stirred solution of 4.1 grams (0.04 mole) of diisopropylamine in 100 ml of tetrahydrofuran was cooled to -78° C., and 17.4 ml (0.04 mole) of 2.3 M n-butyllithium in hexane was added during a 15 minute period. Upon completion of addition, the reaction mixture was stirred at -78° C. for 15 minutes. After this time, 6.4 grams (0.04 mole) of ethyl (trimethylsilyl)acetate was added during a 10 minute period. Upon completion of addition, the reaction mixture was stirred at -78° C. for 30 minutes, and 8.5 grams (0.04 mole) of cyclopropyl (4-trifluoromethylphenyl) ketone was added during a 5 minute period. After this time the reaction mixture was stirred at -78° C. for one hour, at -25° C. for one hour, and finally at ambient temperature for two hours. The reaction was then quenched with aqueous 5% hydrochloric acid. The mixture was then extracted with diethyl ether, and the combined extracts were dried with sodium sulfate. The mixture was filtered, and the filtrate was concentrated under reduced pressure to a residue. The residue was subjected to column chromatography on silica gel. Elution was accomplished using 5% diethyl ether in hexane. The appropriate fractions were combined and concentrated under reduced pressure, yielding 6.0 grams of ethyl 3-cyclopropyl-3-(4-trifluoromethylphenyl)propenoate. The nmr spectrum was consistent with the proposed structure.

Provenance & Evidence