15-クラウン5-エーテル

解説オキシエチレン基が－(OCH2CH2)nの形でつぎつぎにつながって，大環状のポリエチレンエーテル骨格をもつ化合物の総称．－O－と－CH2CH2－が交互につながって王冠の形になっている．たとえば，n＝6のものは18-クラウン-6といわれる．大環状形の中央に，適当な大きさの空間があって，アルカリ金属イオンやアルキルアンモニウムなどの有機陽イオンを取り込み，酸素原子との間に包接化合物をつくる．アルカリイオン捕獲剤，有機合成における相間移動触媒，液体クロマトグラフィーにおけるアミン類分離用の移動相添加剤などとしての用途がある．

用途有機合成触媒、金属の濃縮、分離、回収。

使用15-Crown-5 is used as an efficient phase transfer catalyst and as a complexing agent. It is used to isolate oxonium ion (H7O3)+ salts especially from a solution of tetrchloroauric acid. It catalyzes the O-alkylation of the sodium salts of carboxylic acids in the penicillin and cephalosporin series, thereby facilitating esterification reaction without usage of acid. It is also used to facilitate the Williamson synthesis of ethers with hindered alcohols and sodium hydride. It is used with lithium aluminum hydride, for performing reduction reactions in hydrocarbon solvents. Further, it is involved in the Horner-Wadsworth-Emmons reaction to prepare stilbenes from aldehydes.

一般的な説明15-Crown-5 is a crown ether generally used as a ligand in coordination chemistry because of its strong chelating property with certain alkali cations to form complexes. Some derivatives of 15-crown-5 are used as sensors and probes in different physical-chemical processes, phase-transfer reactions, and selective capture of ions for separation and transport.