An Approach for Highly Enantioselective Synthesis of <i>meta</i>-Disubstituted [<i>n</i>]Paracyclophanes

Abstract

Atroposelective synthesis of <i>meta</i>-disubstituted [<i>n</i>]paracyclophanes is a difficult task in organic chemistry. We describe a facile approach for the synthesis of <i>meta</i>-disubstituted [<i>n</i>]paracyclophanes using Pd-catalyzed enantioselective C-H olefination and sequential reductive cleavage. A wide range of [<i>n</i>]paracyclophanes was obtained with excellent enantioselectivity. Thermodynamic analysis revealed that the rotational barrier of <i>meta</i>-disubstituted [<i>n</i>]paracyclophanes was lower than that of <i>para</i>-disubstituted [<i>n</i>]paracyclophanes. The synthesized planar-chiral [14]paracyclophane showed a bright fluorescence emission and impressive circularly polarized luminescence activity.