Detrifluoroacetylative Generation of Halogenated Enolates: Practical Access to Perhalogenated Ketones and Alkenes

Abstract

Sequential chlorination/fluorination of aromatic trifluoroacetylated ketones gives 1-aryl 2-chloro-2,4,4,4-tetrafluorobutan-1,3-dione hydrates that are used for the synthesis of ketones and alkenes exhibiting a terminal bromochlorofluoromethyl group. The hydrates undergo detrifluoroacetylative cleavage and subsequent bromination in the presence of a copper(II) bisoxazoline catalyst, K₂CO₃, and NBS at room temperature. The corresponding bromochlorofluoromethyl ketones can be applied in Wittig and Horner–Wadsworth–Emmons reactions and dibromoalkenylations.

Key words

fluorine - halogenation - olefination - Wittig reaction - halogens

• References

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