The Synthesis of 5,6‐dihydrobenzo[4,5]imidazo[2,1‐a]isoquinoline Derivatives via Metal‐Free Radical Cascade Pathway

A metal‐free radical relay addition/cyclization of activated alkenes with ethers, cycloalkanes, toluenes, and alcohols has been achieved, leading to a range of functionalization of 5,6‐dihydrobenzo[4,5]imidazo[2,1‐a]isoquinolines with the yield of 43% ‐ 84%. This protocol exhibits advantages of metal‐free, base‐free, and shorter reaction time.