アイテム詳細

要旨

Direct C–H functionalization can quickly increase useful structural and functional molecular complexity^1,2,3. Site selectivity can sometimes be achieved through appropriate directing groups or substitution patterns^1,2,3,4—in the absence of such functionality, most aromatic C–H functionalization reactions provide more than one product isomer for most substrates^1,4,5. Development of a C–H functionalization reaction that proceeds with high positional selectivity and installs a functional group that can serve as a synthetic linchpin for further functionalization would provide access to a large variety of well-defined arene derivatives. Here we report a highly selective aromatic C–H functionalization reaction that does not require a particular directing group or substitution pattern to achieve selectivity, and provides functionalized arenes that can participate in various transformations. We introduce a persistent sulfur-based radical to functionalize complex arenes with high selectivity and obtain thianthrenium salts that are ready to engage in different transformations, via both transition-metal and photoredox catalysis. This transformation differs fundamentally from all previous aromatic C–H functionalization reactions in that it provides direct access to a large number of derivatives of complex small molecules, quickly generating functional diversity with selectivity that is not achievable by other methods.