Tri-tert-butylphosphine is an Efficient Promoter for the Trifluoromethylation Reactions of Aldehydes, Ketones, Imides and Imines

Abstract

A truly catalytic nucleophilic trifluoromethylation reaction of carbonyl compounds with Ruppert’s reagent, Me₃SiCF₃, has been shown to be efficiently promoted by a P(t-Bu)₃-DMF system. Imines were also converted to the desired α-trifluoromethyl amines under similar reaction conditions.

Key words

trifluoromethylation - fluorine - aldehydes - imines - Lewis bases

References and Notes

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18

Typical Experimental Procedure.
Tri-tert-butylphosphine [P(t-Bu)₃, 3.9 mg, 0.019 mmol]) was placed in a round-bottomed flask under N₂. Dry DMF (0.25 mL) and 2-naphthaldehyde (1b, 30 mg, 0.19 mmol) were added. To the stirred solution, Me₃SiCF₃ (57 µL, 0.38 mmol) was added at r.t. The mixture was stirred at r.t. for 0.5 h; the reaction was concentrated under reduced pressure. The residue was chromatographed on silica gel using hexane to afford 2b in 99% yield.