ortho-Borylated trifluoroacetanilides: synthesis and fluoride ion binding properties

Abstract

The o-(pinacolboryl)trifluoroacetanilide (1) has been synthesized and structurally characterized. As indicated by NMR spectroscopy, this novel derivative reacts with fluoride to afford the corresponding fluoroborate derivative [1–F]⁻ in which the boron-bound fluorine atom forms a hydrogen bond with the proton of the trifluoroacetamide functionality. Compound 1 reacts with KHF₂ to afford the corresponding trifluoroborate derivative which has been isolated as a dibenzo-18-crown-6 potassium salt (2). The crystal structure and the ¹H NMR spectrum of this salt confirm the presence of a B–F ··· H–N hydrogen bond.