posted on 2023-11-01, 16:40authored byJie Qiu, Wei Li, Xiaofeng Li, Yongyong Cao, Cheng-Xue Pan, Huaifeng Li
Azomethine imines, broadly known as 1,3-dipoles, efficiently
produce
synthetically and biologically significant dinitrogen-fused heterocycles
via predominantly concerted or ionic pathways. Herein, we describe
a radical-based annulation of azomethine imines utilizing visible-light
photoredox catalysis for the first time. This strategy enables the
synthesis of dinitrogen-fused saturated six-membered cyclic products
that have traditionally been difficult to access. Notably, our process
exhibits exceptional cis diastereoselectivity, controlled
by the anomeric effect. Initial mechanistic investigations reveal
a tandem process comprising intermolecular radical addition and intramolecular
6-exo-trig cyclization. This work illustrates potential
within the realm of visible-light-driven radical cyclization reactions
involving azomethine imines.