Ionic-Liquid-Supported Synthesis:  A Novel Liquid-Phase Strategy for Organic Synthesis

Abstract

Soluble ionic liquids have recently been used as supports for catalyst/reagent immobilization and synthesis in homogeneous solution phase. The wide range of ionic liquid supports available makes their use as supports compatible with most common chemistries. The solubility properties of these ionic liquid supports can be tuned by the variation of cations and anions to make them phase separate from less polar organic solvents and aqueous media. The ionic-liquid-supported species can therefore be purified from the reaction mixture by simple washings. Ionic-liquid-supported catalysts and reagents have been prepared and used, and they are easily recovered and reused. Parallel and combinatorial libraries of small molecules have been synthesized. Ionic-liquid-supported synthesis (ILSS) has been applied to the preparation of oligopeptides and oligosaccharides. The comparison of ILSS with solid-phase synthesis, soluble-polymer-supported synthesis, and fluorous phase synthesis has been highlighted where applicable.

An Improved Protocol for the Direct Asymmetric Aldol Reaction in Ionic Liquids, Catalysed by Onium Ion‐Tagged Prolines

“…The former aldehyde (Table 1, run 6) using the same molar amount of catalyst as in ref. [11] generates up to 70 % more of the aldol product in overall 26 h with respect to four cycles in acetone as solvent and using 30 % of 3. [12] Similarly, an analogous comparison of run 1 of Table 3 shows that our protocol applied to 1a affords up to 37 % more of the aldol with respect to four cycles using 30 % of proline in [bmim]A C H T U N G T R E N N U N G [PF 6 ].…”

Solid-state electrochemical behavior of Keggin-type borotungstic acid single crystal

“…Up to now, the electrochemical behavior of POMs has been studied in many environments, such as aqueous solution [28,29] or ionic liquid [30][31][32][33]. POMs have been studied as monolayers or organic-inorganic hybrids in contact with different supporting electrolytes [34,35], and as single crystals in the absence of external liquid phase [21][22][23][24][25][26].…”

Task Specific Onium Salt as Soluble Support in Multicomponent Synthesis of 4‐Aryl‐2‐amino‐3‐ethoxycarbonyl‐naphthopyrans

“…4 Recently, task specific onium salts supported syntheses have been applied to peptide synthesis, 5 transition metal catalyzed reactions 6 and multicomponent reactions. 7 Task specific onium salts removing most problems of solid phase and soluble polymer 8 supported synthesis, allow for high loading capacity, easy reaction monitoring and product characterization using TLC, NMR, HPLC, MS and IR, and keep all the advantages of previous soluble supports including easy purification by simple filtration and washes.…”