Herein, we report the promising use of n-oligoethylene glycols (oligoEGs) as mutifunctional promoters for nucleophilic-substitution reactions employing alkali metal salts. Among the various oligoEGs tested, pentaethylene glycol (pentaEG) had the most efficient catalytic activity. In particular, when compared with other nucleophiles examined, a fluorine nucleophile generated from CsF was significantly activated by the pentaEG promoter. We also performed various facile nucleophilic-displacement reactions, such as the halogenation, acetoxylation, thioacetoxylation, nitrilation, and azidation of various substrates with potassium halides, acetate, thioacetate, cyanide, and sodium azide, respectively, in the presence of the pentaEG promoter. All of these reactions provided their desired products in excellent yields. Furthermore, the combination of pentaEG and a tert-alcohol medium showed tremendous efficiency in the nucleophilic-displacement reactions (fluorination and methoxylation) of base-sensitive substrates with basic nucleophiles (cesium fluoride and potassium methoxide, respectively). The catalytic role of oligoEGs was examined by quantum-chemical methods. The oxygen atoms in oligoEGs were found to act as Lewis bases on the metal cations to produce the "flexible" nucleophile, whereas the two terminal hydroxy (OH) groups acted as "anchors" to orientate the nucleophile and the substrate into an ideal configuration for the reaction.

Polymer-supported pentaethylene glycols (PSpentaEG) as promising catalysts for nucleophilic fluorination with alkali metal fluoride (MF) could significantly enhance the nucleophilicity of MF and provide simple purification and recycling in the reaction. Furthermore, by their synergistic effect, the combination of PSpentaEG and a tert-alcohol media system showed tremendous efficiency in the fluorination of base-sensitive substrates such as sec-alkyl halide.

1,13-Dichloro-4,7,10-trioxatridecane (2-[2-(1-chloro-2-ethoxy)ethoxy]ethyl chloride) (3a) was synthesized by a chlorination of 1,13-dihydroxy-4,7,10-trioxatridecane (triethylene glycol). And it was treated with imidazole and sodium ethoxide to give the 1N,1N′-tris(oxoethylene)-diimidazole (3b), which was then converted to ionic liquid-type crown ether (ILCE) 3 with a reaction with 1,9-dichloro-3,6-trioxaoctane (2a). Further, the anion of ILCE was exchanged by an anion-exchange method. Ultimately, we developed a very efficient synthetic pathway for ILCEs 1–4 which have various physical and chemical characteristics by a modification of the polyethylene glycol chain length and anions. 85Sr2+ was successfully extracted into the [(3,2)OEtIm][Cl] (3) phase, but it was not extracted into the [(2,2)OEtIm][Cl] (1), [(3,3)OEtIm][Cl] (2), and [(4,3)OEtIm][Cl] (4) phases.

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