Amino Acid-Promoted Reactions in IL Media

The IL medium is most beneficially appUed for asymmetric reactions promoted by hydrophilic amino acid organocatalysts, in particular proline. Amino acids, being poorly soluble in hydrocarbon or ether solvents, are not washed out to the organic phase during products isolation, which allows the catalyst-IL system 

this methodology was extended to acetone derivatives bearing a heteroatom at the a-position to the carbonyl group [27] and to heteroaromatic aldehydes [28]. 

Aldol reactions with cydoaUcanone donors predominantly afford anti-aldols and water and/or another IL additive (up to 10 equiv.) may exert beneficial effect on reaction diastereoselectivity [29]. The IL nature plays an important role here the yield and enantiomeric excess of aldols 1 (R = = H) increased (up to 99%) when 

In the same year, Teo and Chua reported that L-serine fert-butyldiphenylsilyl ether efficiently catalyzed an asymmetric aldol reaction between cycloalkanones and aromatic aldehydes in [bmim][BF4] [40]. The catalyst solution in the IL withstood three recovery cycles however, a progressive decrease of activity caused by the leaching of the siloxy serine catalyst from the IL medium to the ether solution used for extraction of products and a slight decHne of reaction enantioselectivity were recorded. 

Reactions in the Presence oTOther Chiral Organocatalysts in IL Media 

2 tonic Liquids as Recyclable Solvents for Asymmetric Orgonocataiytic Reactions 621 

Organocatalytic reactions in IL media can be induced by primary a-amino acids. In 2008, Lombardo with coworkers showed that aromatic aldehydes could react with cyclic ketones in 1-butyl-l-methylpyrrolidinium trifluoromethane sulfonate ([bmpyr][OTf ) containing the catalytic system arginine/p-toluenesulfonic acid (10mol% each) to give the corresponding aldols in higher yields than in DMSO 

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