Preparation of Tailor-Made Hosts from -Cyclodextrin by Modification of its Cavity

点击翻译按钮获取中文摘要

-Cyclodextrin ( -CD) can include two molecular species in its cavity. When -CD has an appending arene moiety, the moiety can be expected to act as a spacer, which enables -CD to form 1:1 host-guest complexes by narrowing the large cavity. The purpose of this project is preparing many hosts having voids with desired sizes by using spacer moieties different in bulkiness. From this viewpoint, -CD derivatives having ferrocene, naphthalene, anthracene, and pyrene have been prepared. When the -CD derivatives form complexes with guests, the ferrocene moiety moves outward, whereas the naphthalene moiety enters the cavity. The -CD derivatives hving anthracene and pyrene moieties form association dimers, which convert into 1:1 host-guest complexes on guest addition. The association dimer of pryene-appended -CD exhibits excimer emission, whose intensity diminishes on guest addition. This system was used as a sensory system for detecting a variety of organic compounds. In relation to this project, -CDs having two 9-anthracenecarboxylate moieties at ab, AC, AD, and AE glucose residues were prepared. In these substanecs, two anthracene moieties take different mutual orientations, and the cis-photodimer, that is hardly produced in solution, was produced for AB regioisomer. In the case of photoreaction of -CD derivatives having 1-anthracenecarboxylate moieties, there are four possible photodimers. However, syn-head-head dimer was produced from AB and AC, whereas anti-head-head dimer was produced from AD and AE. These results demonstrate that this " -CD template method" can be used to regulate product stereochemistry in organic reaction.