Iodonium nitrate (generated by reaction of iodine chloride with silver nitrate in chloroform–pyridine) reacts with a variety of unsaturated substrates to form the following: 1,4-conjugate addition products of the type alkenyl pyridinium nitrates; alkyliodopyridinium nitrates; products of aromatic iodination of both phenols and anilines; substituted benzodihydrofurans; tetrahydrofurans and tetrahydropyrans; polycyclic bridged ethers; lactones; thiazolines.