Synthesis of optically active folded cyclic dimers and trimers

Ena Kumamoto; Kana Ogawa; Kazunori Okamoto; Yasuhiro Morisaki

doi:10.3762/bjoc.21.124

Synthesis of optically active folded cyclic dimers and trimers

Beilstein J Org Chem. 2025 Aug 11:21:1603-1612. doi: 10.3762/bjoc.21.124. eCollection 2025.

Authors

Ena Kumamoto¹, Kana Ogawa¹, Kazunori Okamoto¹, Yasuhiro Morisaki¹

Affiliation

¹ Department of Applied Chemistry for Environment, School of Biological and Environmental Sciences, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda, Hyogo 669-1330, Japan.

Abstract

Optically active higher-ordered structures, such as one-handed helical and propeller-shaped structures, can be constructed by folding the π-conjugated system using [2.2]paracyclophane as the chiral crossing unit, leading to circularly polarized luminescence (CPL) properties. Chiral cyclic dimers and trimers were synthesized using planar chiral [2.2]paracyclophane-containing enantiopure ribbon-shaped compounds as the chiral monomers. Unicursal π-conjugated systems were folded at the [2.2]paracyclophane units, and exhibited good photoluminescence quantum efficiencies and CPL anisotropy factors. Opposite chiroptical properties were observed between the dimer and trimer, despite the same absolute configuration of the planar chiral [2.2]paracyclophane units, which was reproduced by theoretical studies.

Keywords: [2.2]paracyclophane; circularly polarized luminescence; oligomer; planar chirality.