Chemistry of anthracene-acetylene oligomers: Synthesis and enantiomeric resolution of a chiral 1,8-anthrylene-ethynylene cyclic tetramer

To construct a new type of chiral pi-conjugated system, the title anthracene-acetylene oligomer containing two octyl groups at position 10 of 1,2-alternating anthracene groups was synthesized. Each anthracene unit was connected by Sonogashira coupling, and the tetrameric precursor was cyclized by a cross-coupling reaction to form the desired C-2-symmetric compound. Its enantiomers were resolved by chiral HPLC with a Chiralcel OD column, and the chiroptical properties were investigated by optical rotation ([alpha](D)(23) = -95 and +91) and circular dichroism (CD) measurements. ne structural and spectroscopic features of this oligomer were discussed in terms of the molecular symmetry and the dynamic behavior of the macrocyclic framework.