The Asymmetry is Derived from Mechanical Interlocking of Achiral Axle and Achiral Ring Components –Syntheses and Properties of Optically Pure [2]Rotaxanes–

Abstract

Rotaxanes consisting of achiral axle and achiral ring components can possess supramolecular chirality due to their unique geometrical architectures. To synthesize such chiral rotaxanes, we adapted a prerotaxane method based on aminolysis of a metacyclophane type prerotaxane that had planar chirality, which is composed of an achiral stopper unit and a crown ether type ring component. The prerotaxanes were well resolved using chiral HPLC into a pair of enantiomerically pure prerotaxanes, which were transferred into corresponding chiral rotaxanes, respectively. Obtained chiral rotaxanes were revealed to have considerable enantioselectivity.

Chiral Dualism as an Instrument of Hierarchical Structure Formation in Molecular Biology

“…The origin and potential role of chiral asymmetry in biology have attracted the attention of the research community throughout the years [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Although, at the macroscopic level, nonbiological structures with a homochiral molecular basis are not known, living organisms have been engaged in a unique experiment of creating stable homochiral systems.…”

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.…”

Mechanical Chirality of Rotaxanes: Synthesis and Function

“…Hirose reported a unique synthetic method to prepare mechanically chiral [2]rotaxanes utilizing enantiopure prerotaxanes [20] (Scheme 2). The first attempt toward the asymmetric synthesis of a mechanically planar chiral rotaxane was reported by Takata et al [19] (Scheme 1).…”