iodoaromatic

Iodoaromatic compounds are aromatic molecules in which one or more hydrogen atoms on an aromatic ring have been replaced by an iodine atom. The simplest example is iodobenzene, but the class also includes polyiodinated arenes, such as 4-iodobiphenyl, and heteroaromatics such as 2-iodopyridine. The iodine substituent imparts distinctive reactivity due to its large size and polarizability.

The carbon–iodine bond is relatively weak compared to other aryl–halogen bonds, and aryl iodides readily participate in oxidative addition to transition-metal catalysts. This makes iodoaromatics particularly useful as substrates in cross-coupling and related reactions, where the iodine serves as an excellent leaving group. Iodo substituents also participate in various nucleophilic and metal-catalyzed transformations.

Typical preparation methods include electrophilic iodination of activated arenes, halogen exchange from other aryl halides, and iododesilylation of organosilanes or other precursors with iodine transfer reagents. Iodoaromatics can also be produced from corresponding boron or stannane precursors or via directed iodination of heteroaromatics.

Beyond synthesis, iodoaromatics are valuable intermediates in medicinal chemistry and materials science. They are widely used in cross-coupling reactions such as Suzuki–Miyaura, Sonogashira, and Heck to construct biaryl, alkynyl, and alkenyl aromatics. Some iodoaromatics are employed in radiolabeling with isotopes such as 123I, 125I, or 131I for diagnostic imaging or therapeutic applications.