Lactone synthesis based on atom transfer carbonylation

[GRAPHICS] Five- to seven-membered lactones were prepared from omega-hydroxyalkyl iodides and CO by atom transfer carbonylation without the need for transition metal catalysts, The reaction proceeds via a hybrid radical/ionic mechanism in which the intramolecular alcoholysis of an omega-hydroxyacyl iodide, arising from atom transfer carbonylation, leads to the lactone.