Tetrathiahelicenes: eclectic chiral tools in chemistry and biology

Helicenes, as part of the larger family of helical shaped small molecules, are not only original, aesthetically fascinating, intriguing, flexible chiral systems, but have nowadays reached a high degree of appeal within the scientific community thanks to the association of synthetic challenge to manifold applications that they provide, ranging from nanosciences, chemosensing, material science, asymmetric catalysis and molecular recognition. Among helicenes, tetrathiahelicenes are emerging as the most popular systems, thanks to the remarkable improvements reached in their preparation, and thanks to their unique magnetic, conductive, and optical properties. Other recent interesting applications are emerging in catalysis1 and biology. Such a versatility and eclectic behaviour is closely related to the possibility of obtaining a structural variety still maintaining the defining property of the helical structure. Over the years, our research group has contributed in a significative manner to the development of efficient methods for the synthesis of the helical scaffold of tetrathiahelicenes and its functionalization with the most diverse functional groups. This research has allowed the access to a class of novel variously substituted tetrathiahelicenes. Among them, we have recently developped chiral helicene-based phosphine and phosphine oxide ligands for application in organic and organometallic catalysis, and some interesting results have already been obtained.