Enantioselective Synthesis, Crystal Structure, and Photophysical Properties of a 1,1′- Bitriphenylene-Based Sila[7]helicene

A 1,1'-bitriphenylene-based sila[7]helicene was synthesized with a high ee value by enantioselective double [2+2+2] cycloaddition of a biaryl-linked tetrayne with a silicon-linked bis(propargylic alcohol) as a key step. This sila[7]helicene exhibited a high tolerance toward racemization, which could be explained by the X-ray crystal structure analysis. With respect to the photophysical properties, this sila[7]helicene exhibited a relatively high fluorescence quantum yield and circularly polarized luminescence activity.