Diphenylphosphine oxide
Chemical compound
From Wikipedia, the free encyclopedia
Diphenylphosphine oxide is an organophosphorus compound with the formula (C6H5)2P(O)H. It is a white solid that is soluble in polar organic solvents.[1]
| Names | |
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| Preferred IUPAC name
Diphenyl-λ5-phosphanone | |
| Identifiers | |
3D model (JSmol) |
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PubChem CID |
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| Properties | |
| C12H11OP | |
| Molar mass | 202.19 |
| Appearance | white solid |
| Melting point | 56-57 °C |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Synthesis
Diphenylphosphine oxide can be prepared by the reaction of phosphonic esters, such as diethylphosphite, with Grignard reagents followed by acid workup:[2]
- (C2H5O)2P(O)H + 3 C6H5MgBr → (C6H5)2P(O)MgBr + C2H5OMgBr
- (C6H5)2P(O)MgBr + HCl → (C6H5)2P(O)H + MgBrCl
Alternatively, it may be prepared by the partial hydrolysis of chlorodiphenylphosphine[1] or diphenylphosphine.[3]
Reactions
Diphenylphosphine oxide exists in equilibrium with its minor tautomer diphenylphosphinous acid, ((C6H5)2POH:
- (C6H5)2P(O)H ⇌ (C6H5)2POH
Diphenylphosphine oxide is used in Buchwald-Hartwig coupling reactions to introduce diphenylphosphino substituents.[1]
Thionyl chloride converts diphenylphosphine oxide to chlorodiphenylphosphine.
Organophosphinous acids are deoxygenated with DIBAH. The resulting secondary phosphines are precursors to phosphine ligands.[4]

