ortho-Functionalization of azobenzenes via hypervalent iodine reagents

ortho-Functionalized azobenzenes are much sought after molecular switches, as they may be tuned to absorb in the visible range of light and the (Z)-isomers can have high thermal half-lives. To enable straightforward access to these targets, we have developed a synthetic route via novel ortho-substituted azobenzene-functionalized diaryliodonium salts. Selective transfer of the azobenzene moiety to O-, N-, C- and S-nucleophiles under mild, transition metal-free conditions gives access to an unprecedented range of ortho-substituted azobenzenes. The photoswitching properties of the reagents were investigated and the structure was determined by X-ray crystallography.

Automated summary

This study developed a synthetic route to access ortho-substituted azobenzenes via novel ortho-substituted azobenzene-functionalized diaryliodonium salts. The selective transfer of the azobenzene moiety to various nucleophiles enables the synthesis of a wide range of ortho-substituted azobenzenes. The photoswitching properties and crystal structure of the reagents were investigated.