Electrostatic interaction-assisted regiospecific and oxidant free [4+2] annulation enabled by RhIII catalyzed C−H bond activation

Abstract

A RhIII-catalyzed intermolecular [4+2] annulation reaction, employing N-tosylamide and carboxyl as the directing groups, has been developed herein. The utilization of readily accessible propargylic aminium triflate salts as coupling partners enables a highly efficient strategy for the regiospecific synthesis of isoquinolones and isocoumarins under oxidant-free conditions. In addition, this method is characterized by its facile substrates availability and broad functionality tolerance. Furthermore, preliminary control experiments reveal that electrostatic interaction plays a pivotal role in achieving the reversed regioselectivity observed in this transformation, setting it apart from previous related studies.