Synthesis and kinetic resolution of directional isomers of [2]rotaxanes bearing a lariat crown ether wheel

Abstract

ABSTRACT Rotaxanes can have topological isomers because of their mechanically interlocked axle and wheel components. Directional isomers are formed when the rotaxanes are constructed using an asymmetric axle and a three-dimensional non-symmetrical wheel. In this work, directional isomers of [2]rotaxanes were synthesised using lariat dibenzo-24-crown-8 ether as a non-symmetrical wheel component and a sec-ammonium salt axle. Control over the directional isomer ratio of [2]rotaxanes was achieved, as demonstrated by kinetic resolution via N-acetylation of the [2]rotaxanes.