Borenium-ion-catalyzed hydrogenation of arenes

Non-metal-catalyzed hydrogenation of arenes represents a sustainable and environment-friendly approach for the synthesis of cyclohexane derivatives. Herein, we report the development of a borenium-ion catalyst system which can hydrogenate a number of monocyclic arenes. Additionally, this metal-free catalytic system allows selective partial or full hydrogenation of naphthalene and anthracene by modification of the reaction conditions. Our mechanism studies suggest that the borenium-arene-mediated H-2 splitting takes place before the rate-limiting step and the hydride transfer between the resulting neutral borane and protonated arene is likely the rate-limiting step in the catalytic process.

Automated summary

Non-metal-catalyzed hydrogenation of arenes is a sustainable and environment-friendly approach for the synthesis of cyclohexane derivatives. In this study, a borenium-ion catalyst system was developed to effectively hydrogenate monocyclic arenes. Moreover, the metal-free catalytic system allows for selective partial or full hydrogenation of naphthalene and anthracene by modifying the reaction conditions. Mechanism studies suggest that the H2 splitting mediated by borenium-arene occurs before the rate-limiting step, and hydride transfer between the resulting neutral borane and protonated arene is likely the rate-limiting step in the catalytic process.