Dearomative 2+2 photocycloadditions of indoles with unsaturated functionalities via the energy transfer (EnT) process have been the subject of extensive investigation. In this work, we developed a dearomative 2π+2σ photocycloaddition of unactivated indoles tethered with bicyclo1,1,0butyl units (BCBs) through photoredox catalysis, which enabled the construction of a series of N-heteropolycyclic three-dimensional (3D) molecular architectures. The photoredox catalysis mechanism has been comprehensively validated by a series of control experiments, Stern-Volmer quenching assays, and competition experiments. This protocol offers a novel catalytic pathway that is inaccessible via the EnT route and features a broad substrate scope, a simple reaction system, and straightforward operational procedures.
Chen et al. (Fri,) studied this question.