Homochiral bifunctional L-prolinamide- and L-bis-prolinamide-catalyzed asymmetric aldol reactions performed in wet solvent-free conditions.
In this study, the novel bifunctional homochiral thiourea-L-prolinamides 1-4, tertiary amino-L-prolinamide 5, and bis-L-prolinamides 6 and 7 were prepared from enantiomerically pure (11R,12R)-11,12-diamino-9,10-dihydro-9,10-ethanoanthracene 8 and (11S,12S)-11,12-diamino-9,10-dihydro-9,10-ethanoanthracene ent-8. Highly enantioselective and diastereoselective aldolic intermolecular reactions (up to 95% enantiomeric excess, 93:7 anti/syn) between aliphatic ketones (20 equiv) and a range of aromatic aldehydes (1 equiv) were successfully carried out in the presence of water (10 equiv) and monochloroacetic acid (10 mol%), solvent-free conditions, at room temperature over 24 h using organocatalysts 1-7 (5 mol%). Stereoselective induction using density functional theory-based methods was consistent with the experimental data.
['Huelgas|Gabriela|G|', 'Somanathan|Ratnasamy|R|0000-0003-1220-082X', 'Hernández Pérez|Julio M|JM|', 'Rojas Cabrera|Haydee|H|', 'de la Higuera Macías|Maximiliano|M|', 'Domínguez-Huerta|Alejandra|A|', 'Sabala|Rocío|R|', 'Anaya de Parrodi|Cecilia|C|0000-0001-5619-2513']
D000096:Acetone D000447:Aldehydes D002384:Catalysis D060326:Chemistry Techniques, Synthetic D000077318:Density Functional Theory D007659:Ketones D015394:Molecular Structure D011392:Proline D012997:Solvents D013237:Stereoisomerism D013890:Thiourea
aldol reaction wet solvent-free stereoselectivity 1,2-diamines C2-symmetry axis asymmetric organocatalysis bifunctional prolinamides