(Formylmethyl)triphenylphosphonium Chloride is a useful Wittig reagent. Used as a reactant for Hydroazidation reactions in preparation of a-azido alcohols, Preparation of prodrug (2-hydroxyamino-vinyl)-triphenyl-phosphonium (HVTP) inhibitor of peroxidase activity and apoptosis and Intramolecular [4 + 3] cycloaddition reactions.