Enantioselective synthesis and characterization of [m.n]paracyclophanes.

[m.n]Paracyclophanes ([m.n]PCPs) are widely used in asymmetric catalysis, energy materials, and π-stacked polymers. To date, however, most studies have focused on [2.2]PCPs. The atroposelective synthesis and structural characterization of [m.n]PCPs with variable ansa chain lengths remain underexplored. In this study, we report an N-heterocyclic carbene-catalyzed enantioselective macrocyclization. This method enables the efficient construction of a diverse array of [m.n]PCPs with excellent enantioselectivities. A comprehensive investigation was conducted, including ring strain energy calculations, aromatic interaction energy analysis, racemization barrier measurements, local strain visualization, and systematic geometric analysis. These studies provide detailed insights into the relationship between the macrocyclic structure and properties. The synthetic utility of [m.n]PCPs is demonstrated by a [6.5]PCP-derived thiourea organocatalyst that effectively promotes the asymmetric amination reaction.