Proline ionic properties

Comparably, Barbas HI et al. observed interesting results employing the quite similar ionic liquid 40 as solvent in a proline-catalyzed Mannich reaction (Scheme 2.11a, up to 95% ee) [32], whereas, Wang s group examined the properties of more complex ionic liquids as enamine activation catalysts (Scheme 2.1 lb). The best outcome in terms of yield (up to 99%) and stereoselectivities (91-99% ee) was observed performing the reaction in DMF at -20 °C and using 30 mol% of[EMlm][Pro] 41 [33]. 

Gao H-S, Hu Z-G, Wang J-J et al (2008) Synthesis and properties of novel chiral ionic liquids from L-proline. Aust J Chem 61 521-525... 

Highly polar organocatalysts such as amino acids and peptides are almost insoluble in conventional organic solvents, but they are soluble in ionic liquids. Because of these physical properties, asymmetric syntheses in ionic liquids under biphasic condition have been reported [124], Recently, combinations of solid catalysts and ionic liquids have been studied intensively. The supported ionic liquid phase catalyst is a new generation of the supported liquid-phase catalyst [125]. The supported ionic liquid phase catalyst 232 is readily prepared by adsorption of (S)-proline 13... 

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