Continuous Photoflow Synthesis of Heterohelicenes

Heterohelicenes continue to attract interest for their potential applications as organic chiral materials. To keep up with the demand for novel heterohelicene structures, expedient and scaleable synthetic procedures are required. We report a "Mallory" photocyclization methodology in continuous flow for the synthesis of thia-, oxa-, and azahelicenes. This procedure has been successfully scaled up to 9.8 mmol and can be applied to an iterative modular synthesis.