Zr-promoted cyclization of diynes bearing C2-chirality: synthesis and properties of new chiral conjugated molecules

Conjugated oligomers bearing 4,5,6,7-tetrahydro-5S,6S-dioctyloxybenzothiophene as a central linkage were synthesized by Negishiʹs reagent (n-Bu2ZrCp2) promoted intramolecular cyclization of a diyne and subsequent Suzuki coupling reactions. The chirality in the central linkage originated from tartaric acid, which induced the conjugated backbone of oligomers to exhibit interesting optical activity.