Carboiodanation of arynes: Organoiodine(III) compounds as nucleophilic organometalloids

Organic iodine(III) compounds represent the most widely used hypervalent halogen compounds in organic synthesis, where they usually perform the role of an oxidant or electrophile to functionalize electron-rich or nucleophilic organic compounds. In contrast to this typical reaction mode and the nature of organohalogen compounds in general, we discovered a novel reactivity of organoiodine(III) compounds that behave as organometallic-like nucleophiles toward arynes. Possessing diverse transferable ligands and being supported by a cyclic spectator ligand, the organoiodine(III) compounds undergo addition across the electrophilic C–C triple bond of arynes while retaining the trivalency of the iodine center. This carboiodanation reaction can forge a variety of aryl–alkynyl, aryl–alkenyl, and aryl–(hetero)aryl bonds along with the concurrent formation of an aryl–iodine(III) bond under mild conditions. The newly formed aryl–iodine(III) bond serves as a versatile linchpin for downstream transformations, particularly as an electrophilic reaction site. The amphoteric nature of the iodine(III) group as a metalloid and a leaving group in this synthetic sequence enables the flexible and expedient synthesis of extended π-conjugated molecules and privileged biarylphosphine ligands, where all the iodine(III)-containing compounds can be handled as air- and thermally stable materials.