Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, 565-0871, Japan.
Chempluschem. 2020 Aug;85(8):1928-1933. doi: 10.1002/cplu.202000522.
The host-guest chemistry and applications of cyclodextrins in aqueous media is well established. However, a comprehensive study in organic solvents is lacking. Here, we report the design and synthesis of 6-O-tert-butyldimethylsilylated β-cyclodextrin (TBDMS-β-CD) bearing various aromatic substitutions at the 2-O position and their inclusion complex formation with aromatic guests in nonpolar organic solvents. Compared to the parent TBDMS-β-CD, these derivatives exhibit at least a 10-fold increase in inclusion ability toward pyrene through cooperative guest binding with the CD cavity and the aromatic substituents at the 2-O position. The type of the aromatic substituent largely affects the chiral recognition ability of TBDMS-β-CD toward 1-(1-naphthyl)ethylamine in cyclohexane. A TBDMS-β-CD derivative with a p-tolyl substituent has a remarkable chiral selectivity for the (S)-1-(1-naphthyl)ethylamine over the corresponding (R)-isomer (K /K =4.1±0.5), whereas a TBDMS-β-CD derivative with a 2-picolyl substituent shows the inverse chiral selectivity (K /K =8.7±0.6).
环糊精在水相中的主体-客体化学及其应用已经得到了很好的研究。然而，在有机溶剂中的综合研究却很缺乏。在这里，我们报告了在 2-O 位带有各种芳香取代基的 6-O-叔丁基二甲基硅基-β-环糊精（TBDMS-β-CD）的设计和合成，以及它们在非极性有机溶剂中与芳香客体的包合形成。与母体 TBDMS-β-CD 相比，这些衍生物通过与 CD 空腔和 2-O 位的芳香取代基的协同客体结合，对芘的包合能力至少增加了 10 倍。芳香取代基的类型对 TBDMS-β-CD 在环己烷中对 1-（1-萘基）乙胺的手性识别能力有很大影响。带有对甲苯基取代基的 TBDMS-β-CD 衍生物对（S）-1-（1-萘基）乙胺具有显著的手性选择性，而带有 2-吡啶基取代基的 TBDMS-β-CD 衍生物则表现出相反的手性选择性（K /K =4.1±0.5）。
