Phosphonium SF₅⁻ Salts Derived from Sulfur Hexafluoride as Deoxyfluorination Reagents

Abstract

Sulfur based deoxyfluorination reagents are usually derived from the corrosive gas SF4. Herein, we report the synthesis and properties of an easily accessible phosphonium salt [(tmg)3PF]+SF5– (1) which was obtained from the reaction of sulfur hexafluoride (SF6) with tris(tetramethylguanidinyl)phosphine. The performance of this crystalline SF5– salt as a reagent in deoxyfluorination reactions was investigated together with a second SF5– salt [(R1)3PF]+SF5– (2) containing bulky substituents (R1 = 1,3‐di‐tert‐butylimidazolidin‐2‐ylidenamino). Both reagents proved to be effective for the deoxyfluorination of various functional groups including alcohols, anhydrides, and amides.