Diversity-oriented synthesis of 3-iodochromones and heteroatom analogues via ICl-induced cyclization.

The ICl-induced cyclization of heteroatom-substituted alkynones provides a simple, highly efficient approach to various 3-iodochromones and analogues. This process is run under mild conditions, tolerates various functional groups, and generally provides chromones in good to excellent yields. Subsequent palladium-catalyzed transformations afford a rapid increase in molecular complexity and a convenient preparation of a wide range of functionally substituted chromones, furans, and polycyclic compounds. Iodothiochromenones and iodoquinolinones are also prepared by similar ICl-induced cyclizations.