Preparation of Novel Tetrathia[7]helicenes

Significance

Synthetic routes leading to functionalized tetrathia[7]helicenes have been developed. Initial formation of 3 via double Suzuki coupling is followed by functionalization and ring-closure (or with steps reversed) to give the desired helicenes in modest to good yields. Intermediate 3 could also be accessed by McMurry coupling (not shown). The physical and chemical properties of the helicenes are currently being studied, and attempts to prepare optically active samples are also underway.