iodobenzene

Iodobenzene is an organoiodine compound with the formula C6H5I, consisting of a benzene ring bearing a single iodine substituent. It is used as an aryl halide substrate in organic synthesis due to the relatively reactive carbon–iodine bond and its ability to participate in a range of catalytic processes.

Iodobenzene can be prepared by several methods. It is accessible via electrophilic iodination of benzene using iodine in the presence of a Lewis acid catalyst, though this route can be sluggish for unactivated rings. A more versatile approach converts anilines to iodoarenes through the Sandmeyer-type reaction: aryldiazonium salts are treated with iodide and a copper catalyst to yield iodobenzene. Iodination of activated arenes and heteroarenes with appropriate oxidants or iodinating reagents is another practical route.

In terms of reactivity, the C–I bond in iodobenzene is relatively labile for oxidative addition, making it a preferred substrate for palladium- and copper-catalyzed cross-coupling reactions such as Suzuki-Miyuara, Sonogashira, and Negishi couplings. This facilitates the synthesis of biaryl compounds, heteroaryl derivatives, and various substituted arenes. Iodobenzene is also used as a precursor for other aryl halides and functionalized aromatic compounds through standard organoiodine chemistry.

Safety and handling considerations include its irritant nature and appropriate precautions for handling volatile organoiodines. It should be used in well-ventilated areas with suitable protective equipment, and waste should be disposed of according to applicable regulations.