Syntheses[edit]
Phosphine oxides are frequently generated as a by-product of the Wittig reaction:
R3PCR'2 + R"2CO → R3PO + R'2C=CR"2
Another common route to phosphine oxides is the thermolysis of phosphonium hydroxides. In the laboratory, phosphine oxides are usually generated by the oxidation, often accidentally, of tertiary phosphines:
R3P + 1/2 O2 → R3PO