Deoxygenative Fluorination of Phosphine Oxides: A General Route to Fluorinated Organophosphorus(V) Compounds and Beyond
Dustin Bornemann, Cody Ross Pitts, Lionel Wettstein, Fabian Brüning, Sebastian Küng, Liangyu Guan, Nils Trapp, Hansjörg Grützmacher, Antonio Togni
Abstract
Abstract Fluorinated organophosphorus(V) compounds are a very versatile class of compounds, but the synthetic methods available to make them bear the disadvantages of 1) occasional handling of toxic or pyrophoric P III starting materials and 2) a dependence on hazardous fluorinating reagents such as XeF 2 . Herein, we present a simple solution and introduce a deoxygenative fluorination (DOF) approach that utilizes easy‐to‐handle phosphine oxides as starting materials and effectively replaces harsh fluorinating reagents by a combination of oxalyl chloride and potassium fluoride. The reaction has proven to be general, as R 3 PF 2 , R 2 PF 3 , and RPF 4 compounds (as well as various cations and anions derived from these) are accessible in good yields and on up to a multi‐gram scale. DFT calculations were used to bolster our observations. Notably, the discovery of this new method led to a convenient synthesis of 1) new difluorophosphonium ions, 2) hexafluorophosphate salts, and 3) fluorinated antimony‐ and arsenic‐ compounds.