Iodobenzene-catalysed iodolactonisation using sodium perborate monohydrate as oxidant

A convenient approach has been developed for iodolactonisation using iodobenzene as catalyst. The active reagent was generated in situ with tetra-n-butylammonium iodide (TBAI) and hypervalent iodine reagent, diacetoxyiodobenzene (PIDA). PIDA, in turn, was generated in situ using a catalytic amount of iodobenzene with sodium perborate monohydrate as the stoichiometric oxidant. A variety of olefinic acids including δ-pentenoic acids, δ-pentynoic acids and δ-hexynoic acid gave high yields of lactones using this methodology.