Barton–Kellogg reaction

Triphenylphosphine reacts as a nucleophile, opening the three-membered ring to form a sulfaphosphatane.

In a manner similar to the Wittig reaction, this structure then expels triphenylphosphine sulfide to produce an alkene.

The diazo compound can be obtained from a ketone by reaction with hydrazine to a hydrazone followed by oxidation.

Many reagents exist for this conversion for example silver(I) oxide and (bis(trifluoroacetoxy)iodo)benzene.

[7] The thioketone required for this reaction can be obtained from a ketone and phosphorus pentasulfide.