Concise Synthesis of Polysubstituted Carbohelicenes by a C−H Activation/Radical Reaction/C−H Activation Sequence.

Disclosed herein is the merging of C−H activation and radical chemistry, enabling rapid access to a structurally diverse family of fused carbohelicenes through the fusion of α‐acetylnaphthalenes with alkynes under oxidative conditions. This cascade process exhibits exquisite chemoselectivity and regioselectivity. The reaction pathway was analyzed by intermediate separations, control experiments, radical trapping, EPR, MALDI‐TOF‐MS, and ESI‐HRMS experiments, and shown to involve a C2−H activation/radical reaction/C8−H activation relay. Carbohelicenes were synthesized with unparalleled ease in a C−H activation/radical reaction/C−H activation sequence starting from α‐acetylnaphthalenes and alkynes. This process exemplifies the high compatibility of ionic and radical transformations. [ABSTRACT FROM AUTHOR]