Synthesis and Chiroptical Properties of Double-Helical (M)- and (P)‑o‑Oligophenylenes

All of the M and P isomers of optically pure oligophenylenes with 6, 8, 10, and 12 phenyl rings were synthesized and fully characterized. The Suzuki cross-coupling reaction has been revealed to be a viable strategy in the syntheses of tetraphenylene derivatives, which, together with the copper-mediated oxidative cross-coupling reaction, were employed in the quest for the oligophenylenes. X-ray diffraction analysis in combination with specific rotation and circular dichroism spectroscopy unambiguously identified the unique covalent double-helical frameworks of these oligophenylene molecules.