Chirality due to helical shape.

•	Helicenes are a further another example of compounds that lack asymmetric carbon atoms yet are chiral. Helicenes’ chirality results from the fact that clockwise and counterclockwise helices are non-superimposable.

•	Examine the following hexahelicenes (refcodes: HEXHEL and MEHXHE). In both structures see how one side of the molecule must lie above the other because of crowding.