jodoarenen

Jodoarenen are a class of organoiodine compounds derived from arenes in which one or more hydrogen atoms on an aromatic ring have been replaced by iodine. They include monoiodoarenes, diiodoarenes, and higher-order polyiodinated arenes. They are valued in organic synthesis for their reactivity as electrophilic substrates and as versatile leaving groups in catalytic cross-coupling reactions.

Nomenclature and structure: The parent system is benzene and its substituted derivatives. Substituents influence regioselectivity of iodination; common examples are iodobenzene and diiodobenzenes. Iodoarenes are typically prepared from corresponding arenes via electrophilic substitution with iodine sources or through halogen exchange from brominated or chlorinated arenes.

Preparation methods: Direct iodination uses iodine with oxidants or Lewis acids; directed iodination employs directing groups to achieve ortho or para substitution; alternative routes include iododesilylation of silylarenes, or halogen exchange from aryl bromides using iodide sources under catalysis. Radiolabeled iodoarenes incorporating isotopes such as iodine-123 or iodine-125 are prepared for imaging.

Properties and reactivity: The carbon–iodine bond in aryl iodides is relatively weak among aryl halides, making them especially reactive in palladium- and nickel-catalyzed cross-coupling reactions. They serve as electrophilic partners in Suzuki-Miyaura, Sonogashira, and related couplings, and can undergo lithiation or metal-halogen exchange for further transformations.

Applications and significance: Jodoarenes are widely used as intermediates in pharmaceutical synthesis, agrochemicals, and materials science. They also provide routes to complex polycyclic structures through sequential or selective functionalization. Safety concerns include toxicity and environmental considerations for some iodinated compounds.