Effective Synthesis and Modification of α-Cyclodextrin-Based [3]Rotaxanes Enabling Versatile Molecular Design

One-pot synthesis of various alpha-cyclodextrin-(alpha-CD-) based [3]rotaxanes in water and their structural modifications are discussed in detail. Pseudo[3]rotaxane was prepared from alpha-CD and alpha,omega-diaminododecane in water (above 100 g, quantitative yield in a 1 L flask). Successive urea-forming end-capping reactions with isocyanate in water selectively afforded [3]rotaxane with head-to-head structured alpha-CDs. The yields were varied by bulkiness and functionality of end-capping agents. Significant modifications of the axle end and wheel OH group of the [3]rotaxanes were performed by the Suzuki coupling with arylboronic acids and by the perfect acylation with acid anhydrides, respectively.