Rotaxanes Functionalized by Chirality: Novel Rotaxanes Consisting of Binaphthol-Based Chiral Crown Ether

Abstract

A chiral crown ether 1 was synthesized from (R)-1,1′-bi-2-naphthol. Chiral rotaxanes were prepared by end-capping of pseudorotaxanes consisting of 1 and secondary ammonium salts. An ammonium salt bearing terminal anthracene group gave stable pseudorotaxane. Chiral induction was observed during end-capping by radical conjugate addition of a bulky thiol to the pseudorotaxane bearing methacrylate group at the terminus.

Chiroptical inversion of a planar chiral redox-switchable rotaxane

“…13 Chiral rotaxanes may be chiral from inclusion of classical stereogenic elements or by virtue of being mechanically planar chiral. Since then, several examples followed, [14][15][16][17][18][19][20][21][22][23][24][25] in which the mechanically interlocked structure was used to induce directionality in polymers, [26][27][28] for sensing, [29][30][31] and to act as an enantioselective catalyst. 32 Today, sophisticated synthetic protocols allow an efficient enantioselective synthesis.…”

Acid/base controllable molecular switch based on a neutral phenanthroline guest penetrated pseudorotaxane

“…In the NOESY spectra of the pseudorotaxane 1…2a in d-chloroform as shown in Fig. 5(a), clear correlations were observed between the benzylic phenyl protons (f) of the macrocycle 1 and proton (2) of phenanthroline (2a), benzylic phenyl protons (g) of the macrocycle 1 and protons (4, 5) of phenanthroline (2a), benzylic phenyl protons (f) of the macrocycle 1 and protons (2) of phenanthroline (2a), and the oxyethylene protons (h, i, j) of the macrocycle 1 and protons (4,5) of phenanthroline (2a), confirming that phenanthroline (2a) was incorporated within the macrocycle 1 in d-chloroform. When 3 drops of trifluoroacetic acid as an acid stimulus were added into the pseudorotaxane 1…2a in d-chloroform, no distinct cross peaks were observed between the protons (f, g, h, i, j) of the macrocycle 1 and the protons (2,4,5) of phenanthroline (2a) in the NOESY spectra as shown in Fig.…”

“…1 Moreover, intense recent research has been focused on technological applications of exploiting rotaxanes and catenanes as molecular sensors 2,3 and catalysts. 4 For example, Hiratani et al 3 reported that three-dimensional cavities between axles and wheels in the rotaxanes are capable of binding particular alkali metal cations and one enantiomer of an aminoalcohol selectively.…”

Chirality in rotaxanes and catenanes

“…17a ). 53 More recently, Takata and co-workers reported chiral rotaxanes ( R )- 41 and observed diastereoselective N -oxidation when rotaxanes ( R )- 41 were treated with dimethyldioxirane ( Fig. 17b ).…”