All Carbon Helicenes and π‐Extended Helicene Derivatives

Atomic precise chiral molecules with all‐hydrocarbon backbones, such as helicenes and related π‐extended derivatives, attract critical interests due to their great application potential in many fields (e. g., chiral optical materials, asymmetric catalysis, and molecular machines). Herein, the main development of these molecules in the past decade was summarizes, including enantioselective synthesis of helicenes, helicene with extension along with perpendicular to the helical axis, as well as π‐extended following both directions, namely along with helix axis and perpendicular to the helical axis direction. Recent research on hydrocarbon helicene molecules is summarized with an emphasis on the synthesis and properties of chiral π‐extended helicenes. Enantioselective synthetic processes for helicenes, helicenes with π‐extension perpendicular to the helical axis, as well as following both directions are also summarized and commented in a comprehensive manner.