Cleavage of PO in the Presence of P–N: Aminophosphine Oxide Reduction with In Situ Boronation of the PIII Product. Issue 42 (11th September 2013)

• Record Type: Journal Article
• Authors: Kenny, Niall P.; Rajendran, Kamalraj V.; Jennings, Elizabeth V.; Gilheany, Declan G.
• Is Part Of: Chemistry. Volume 19:Issue 42(2013)
• Page Start: 14210
• Page End: 14214
• Publication Date: 2013-09-11
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201302907
• Languages: English
• ISSNs: 0947-6539

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>In contrast to tertiary phosphine oxides, the deoxygenation of aminophosphine oxides is effectively impossible due to the need to break the immensely strong and inert PO bond in the presence of a relatively weak and more reactive PN bond. This long‐standing problem in organophosphorus synthesis is solved by use of oxalyl chloride, which chemoselectively cleaves the PO bond forming a chlorophosphonium salt, leaving the PN bond(s) intact. Subsequent reduction of the chlorophosphonium salt with sodium borohydride forms the P^III aminophosphine borane adduct. This simple one‐pot procedure was applied with good yields for a wide range of PN‐containing phosphoryl compounds. The borane product can be easily deprotected to produce the free P^III aminophosphine. Along with no observed PN bond cleavage, the use of sodium borohydride also permits the presence of ester functional groups in the substrate. The availability of this methodology opens up previously unavailable synthetic options in organophosphorus chemistry, two of which are exemplified.</p> </abstract>