Acylative Uni-directional Transport on Level Periodic Potential Surface Using a Rotaxane Platform with a Isopropylidene Separator

A rotaxane consisting of DB24C8 and sec-ammonium salt that has a Troc-protected ammonium group beyond an isopropylidene separator was prepared. After rapid acylation of the ammonium moiety to transfer the DB24C8 mover, the Troc group was deprotected. The DB24C8 mover was transferred to the newly formed ammonium moiety over the isopropylidene separator. Second rapid acylation of the ammonium moiety induced efficient active transport due to the steric hindrance of the isopropylidene group. Thus, long-range uni-directional transport on the level periodic potential surface would be possible with the isopropylidene separator.