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

One‐pot synthesis of various α‐cyclodextrin‐(α‐CD‐) based [3]rotaxanes in water and their structural modifications are discussed in detail. Pseudo[3]rotaxane was prepared from α‐CD and α,ω‐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 α‐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.