Synthesis and Chiroptical Properties of Stereogenic <i>π</i>-Conjugated Compounds

Molecules with high symmetry and structural aesthetics have attracted attention of many organic chemists due to their synthetic challenges and their potential for chiroptical properties. Our group has been engaged in the synthesis and functional exploration of highly symmetric π-conjugated compounds incorporating axial (binaphthyl) and planar chirality ([2.2]paracyclophane) as chiral elements. X-ray crystallography has revealed the structures, and their chiroptical properties such as circular dichroism (CD) and circular polarized luminescence (CPL) have been investigated. We have also developed chiral-induced additives based on π-extended planar chiral [2.2]paracyclophane. A significant amplification of CPL was observed with only 3 wt% doping to the achiral π-conjugated luminescent polymer. In this review, we summarize the synthesis and properties of the chiral compounds which we have developed so far. We sincerely believe that this paper will be a source of ideas not only for researchers in structural organic chemistry and materials organic chemistry who work with π-conjugated compounds, but also for synthetic organic chemists who work with chiral compounds, especially those who are involved in asymmetric synthesis.