Reactions of alkynes with iodine and potassium iodide in acetic acid in the presence of nitrates. Simple synthesis of 1-iodo-2-nitroalkenes

Terminal and internal alkynes react with I₂ or KI and nitrates in acetic acid under mild conditions to give the corresponding 1-iodo-2-nitroalkenes as the major products. The effect of the reactant nature and reaction conditions on the yield of products was studied. Oxygen was found to play an important role in the formation of the target products. A possible mechanism of the reaction includes a series of redox transformations of I₂ or I^- and NO^- ₃ to form INO₂ which then adds to alkynes by a radical path. In reactions with potassium iodide, oxygen acts as an additional oxidant which converts NO into active nitrogen dioxide.