A switchable [2]rotaxane with two active alkenyl groups

• Xiu-Li Zheng,
• Rong-Rong Tao,
• Rui-Rui Gu,
• Wen-Zhi Wang and
• Da-Hui Qu

Beilstein J. Org. Chem. 2018, 14, 2074–2081, doi:10.3762/bjoc.14.181

• polymers. Keywords: alkenyl bond; functional crown ether; stimuli-responsiveness; switchable rotaxane; Introduction Along with the development of supramolecular chemistry, much attention has been paid to the design and synthesis of novel and complicated mechanical interlocked molecules (MIMs) [1][2][3][4

• base makes the DB24C8 moiety slide to the amide station and the macrocycle could move back to the DBA recognition site when acid was added (Scheme 1). The synthesis routes of the target compound [2]rotaxane R1 are shown in Scheme 2. Compounds 1 [32], 2 [33], 6 [34], 7 [35] and functional crown ether 9

• ), H11 (peak C) (around the DBA recognition site) and methylene protons on the functional crown ether indicate that the DB24C8 macrocycle was located on the DBA site, corresponding to the structure of [2]rotaxane R1. After addition of 2 equiv DBU to the solution of R1, the NOE correlations between the