1(R),2(R)-Bis[(S)-prolinamido]cyclohexane/[bmim][BF4] ionic liquid as an efficient catalytic system for direct asymmetric aldol reactions

Recyclable Stereoselective Catalysts

“…Kucherenko et al developed a new highly active and recoverable (three cycles) catalytic system based on bis(prolinamide)cyclohexane 212 /[bmim][BF 4 ] for asymmetric aldol reactions between several alkyl ketones and nitrobenzaldehyde. The respective 3-hydroxyketones were prepared in moderate to good yields in the presence of a 3-fold excess of ketone with good enantioselectivities (6−70% ee) …”

“…The respective 3-hydroxyketones were prepared in moderate to good yields in the presence of a 3-fold excess of ketone with good enantioselectivities (6-70% ee). 432…”

Non-covalent immobilization of asymmetric organocatalysts

“…Other reactions such as cross-aldol reaction between aldehydes 48 and asymmetric a-aminoxylations 49,50 could also be performed in similar reaction systems (Scheme 17). The proline derivatives such as L-prolinamide (28), 51 bis(prolinamide)cyclohexane (29), 52 secondary-tertiary diamine (30) 53 and chiral zwitterions (31) 54 could also be immobilized in IL with good catalysts' reusability (Scheme 18). In most of the catalytic system mentioned above, the catalyst could be recycled and reused for at least 3 times.…”

Organocatalytic Reactions Under Unusual Conditions

“…have prepared prolinamide catalyst C51 and tested it in the aldol reaction of 4-nitrobenzaldehyde with acetone and other ketones in ionic liquids [85]. The reaction was much faster than the one catalyzed by (S)-proline.…”