Recent advances in the synthesis of multiple helicenes

Multiple helicenes, as helically twisted polycyclic frameworks with extended π-conjugated systems, have attracted growing attention due to their unique topologies, tunable chiroptical properties, and potential applications in chiral materials and organic electronics. In this review, we provide a systematic overview of the recent advances in the field of multiple helicenes and propose a concise classification strategy that classifies them into linear, cyclic, and cross-linked types. Based on this classification, we further summarize and highlight a range of efficient synthetic strategies that facilitate the construction of multiple helicenes. We hope this review will provide the design inspiration of multiple helicenes and further be helpful for the development of helicene chemistry.