The Mild and Efficient Method of Rotaxane Syntheses and Its Applications

我們發現benzylic azides與trialkyl phosphite作用形成dialkyl phosphoramidate的反應，可相當有效率地被應用於不同孔徑的大環分子與dibenzylammonium ion (DBA+) 之辨識系統，來合成[2]車輪烷分子。若以二十四員環之dibenzo-[24]crown-8 (DB24C8)，或是與DBA+之錯合能力相當弱的di(p-toluidine)[24]crown-8 (DPT24C8)，則diethyl phosphoramidate可作為適當之封鎖基；若大環分子為二十六員環，則須以dibutyl phosphoramidate作為封鎖基。
我們亦合成一個具有雙重辨識單元的大環分子，不但可與DBA+錯合，更可利用鈀(II)離子之四配位特性，連接大環分子與吡啶衍生物，以形成準車輪烷的結構。我們分別利用這兩種辨識單元，合成出對應的[2]車輪烷分子。

The mild and efficient reaction between trialkyl phosphite and benzylic azides allows us to construct rotaxanes utilizing the recognition motif of macrocycles, with different sizes, and dibenzylammonium ion (DBA+). In the case of 24-membered macrocycles, such as dibenzo[24]crown-8 (DB24C8) and di(p-toluidine)[24]crown-8, which binds DBA+ ions much more weakly than does DB24C8, diethyl phosphoramidate is a suitable stopper. For 26-membered macrocycle, the larger dibutyl phosphoramidate is needed to act as a stopper.
The dual-use macrocycle, which owns double recognition motif was also synthesized. Not only complexing with DBA+, it also attached with the derivatives of pyridine via Pd(II). Applying both recognition motifs, rotaxanes are successfully synthesized respectively.