Formal Electrophilic Phenylation Reaction with Tropylium Ion

Arylation reaction is an important transformation in synthetic chemistry as aryl building blocks are ubiquitous in valuable organic frameworks. Traditionally, this type of reaction has been carried out either via biaryl coupling reactions or with the use of reactive intermediates such as arynes or aryl radicals. Direct electrophilic arylation reactions have been rarely reported in literature, as the required arenium building blocks are often unstable or inaccessible. To develop a new strategy for such transformation, we herein introduce the development of a formal phenylation reaction, which proceeds via an electrophilic cycloheptatrienylation with tropylium ion, followed by an oxidative ring-contraction.