Perfluorooxosulfate Salts as SOF₄-Gas-Free Precursors to Multidimensional SuFEx Electrophiles

Area of Science:

• Organic Chemistry
• Click Chemistry
• Fluorine Chemistry

Background:

• Sulfur(VI) Fluoride Exchange (SuFEx) chemistry is a powerful tool for modular synthesis.
• Multidimensional SuFEx hubs, like sulfurimidoyl difluorides, enable complex molecular architectures.
• The limited availability of thionyl tetrafluoride (SOF4) restricts the widespread use of these hubs.

Purpose of the Study:

• To identify and validate a new, accessible SuFEx hub reagent.
• To develop a practical synthetic route to sulfurimidoyl fluorides.
• To expand the scope of multidimensional SuFEx chemistry.

Main Methods:

• Preparation of silver pentafluorooxosulfate (AgOSF5) via AgF2-mediated oxidation of SOCl2.
• Reaction of AgOSF5 with primary amines to form sulfurimidoyl fluorides.
• Extension of the methodology to the trifluoromethyl analogue, AgOSF4CF3.

Main Results:

• AgOSF5 demonstrates reactivity comparable to SOF4 as a SuFEx hub.
• High yields of sulfurimidoyl fluorides were achieved using the AgOSF5 method.
• The synthetic workflow is effective for both parent and trifluoromethylated analogues.

Conclusions:

• Silver pentafluorooxosulfate (AgOSF5) provides a viable and accessible alternative to SOF4 for SuFEx chemistry.
• This work significantly broadens the accessibility of multidimensional SuFEx hubs.
• The proposed AgOSF4X salts offer a general route to azasulfur SuFEx electrophiles from commercial sources.