Thia-Bridged Triarylamine Hetero[4]Helicenes: Regioselective Synthesis and Functionalization

Thia-bridged triarylamine hetero[4]helicenes (TBTH-[4]H) are a peculiar class of geometrically stable [4]helicenes that have shown promising applications as organic electronic materials. Their structure comprises a bis-phenothiazine moiety, with a nitrogen atom and an aromatic ring in common, forced into a helix-shaped arrangement by four carbon–sulfur bonds. We describe a detailed study on the scope and application of the electrophilic sulfur insertion path to TBTH[4]H, with particular emphasis on the regioselective preparation of asymmetric (not dissymmetric) derivatives.