Diiodotriphenylphosphorane

Triphenylphosphine diiodide (Ph₃P. I₂) can be used as a reagent:

• To facilitate the conversion of alcohol, thiol, and enol functional groups into alkyl iodides via formation of alkoxyphosphonium iodide.
• To prepare β-iodo-α,β-unsaturated ketones from cyclic β-diketones in the presence of triethyl amine.
• In the synthesis of alkyl nitrates from alcohols.
• In the Beckmann rearrangement reaction to synthesize lactams from cycloalkanone oxime.
• For the preparation of aromatic and aliphatic carboxylic acid esters in the presence of N,N-dimethylaminopyridine.

Ph₃P. I₂ can also be used to reduce graphene oxide for the production of graphene nanosheets under mild and environmentally friendly conditions.