Electrophilic Phosphonium Cation-Mediated Phosphane Oxide Reduction Using Oxalyl Chloride and Hydrogen

Arne J Stepen; Markus Bursch; Stefan Grimme; Douglas W Stephan; Jan Paradies

doi:10.1002/anie.201809275

Electrophilic Phosphonium Cation-Mediated Phosphane Oxide Reduction Using Oxalyl Chloride and Hydrogen

Angew Chem Int Ed Engl. 2018 Nov 12;57(46):15253-15256. doi: 10.1002/anie.201809275. Epub 2018 Oct 17.

Authors

Arne J Stepen^{1

2}, Markus Bursch³, Stefan Grimme³, Douglas W Stephan², Jan Paradies¹

Affiliations

¹ Department of Chemistry, University of Paderborn, Warburger Strasse 100, 33098, Paderborn, Germany.
² Department of Chemistry, University of Toronto, 80 St. George St, Toronto, Ontario, M5S3H6, Canada.
³ Mulliken Center for Theoretical Chemistry, University of Bonn, Beringstr. 4, 53115, Bonn, Germany.

PMID: 30230149
DOI: 10.1002/anie.201809275

Abstract

The metal-free reduction of phosphane oxides with molecular hydrogen (H₂ ) using oxalyl chloride as activating agent was achieved. Quantum-mechanical investigations support the heterolytic splitting of H₂ by the in situ formed electrophilic phosphonium cation (EPC) and phosphane oxide and subsequent barrierless conversion to the phosphane and HCl. The reaction can also be catalyzed by the frustrated Lewis pair (FLP) consisting of B(2,6-F₂ C₆ H₃ )₃ and 2,6-lutidine or phosphane oxide as Lewis base. This novel reduction was demonstrated for triaryl and diaryl phosphane oxides providing access to phosphanes in good to excellent yields (51-93 %).

Keywords: electrophilic phosphonium cation; frustrated Lewis pair; hydrogenation; phosphane; phosphane oxide.

Abstract

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