A Co-conformationally “Topologically” Chiral Catenane

Abstract

Catenanes composed of two achiral rings that are oriented (C nh symmetry) because of the sequence of atoms they contain are referred to as topologically chiral. Here, we present the synthesis of a highly enantioenriched catenane containing a related but overlooked “co-conformationally ‘topologically’ chiral” stereogenic unit, which arises when a bilaterally symmetric C nv ring is desymmetrized by the position of an oriented macrocycle.

The Final Stereogenic Unit of [2]Rotaxanes: Type 2 Geometric Isomers

“…Our simple, first-principles approach has allowed us to unambiguously identify and define all the possible conditional stereogenic units of rotaxanes and catenanes and confirm that, now that a previously overlooked MGI-2 rotaxane stereochemistry has been found, the pantheon of unique stereogenic units is complete. Based on this analysis, methods exist to stereoselectively synthesize all conditional mechanical stereogenic units of [2]catenanes and [2]rotaxanes apart from MGI-2 rotaxanes; although until 2014, chiral stationary phase high-performance liquid chromatography (HPLC) was required to produce enantioenriched samples of mechanically chiral molecules since this time, methodologies for the stereoselective synthesis of MPC ,,, and MAC catenanes and rotaxanes have been disclosed. Similarly, the first stereoselective synthesis of MGI-1 rotaxanes was reported in 2005 using calixarene rings, and since then many examples based on cone-shaped macrocycles, and more recently simple prochiral rings, , have been reported.…”

Dynamic mechanostereochemical switching of a co-conformationally flexible [2]catenane controlled by specific ionic guests

“…Other co-conformations of C are unlikely to be C2 symmetric although some of them are also chiral. 84,85 Further structural details of the sulfate complex are revealed by single crystal X-ray diffraction analysis (Figure 5). Single crystals of the sulfate complex were obtained by slow vapor diffusion of diisopropyl ether into a DMF solution of C in the presence of 10 eq.…”

Triphasic circularly polarized luminescence switch quantum simulation of a topologically chiral catenane

“…[16][17][18][19] However, chiral catenanes defy this conventional wisdom by showcasing chirality without any inherent molecular asymmetry in their loops. [20][21][22] In this context, the emergence of a chiral topology in these entangled molecules offers the possibility to study the intricate interplay between the topological features and the circularly polarized luminescence (CPL). Notwithstanding the burgeoning of MIMs in many research articles, [23][24][25][26] their use as chiral emitters is still extremely limited: in fact, very few examples of CPL-active mechanically interlocked molecules are reported in the literature [27][28][29][30] and just one in this chemical elite is a catenane.…”