Homochiral bifunctional L‐prolinamide‐ and L‐bis‐prolinamide‐catalyzed asymmetric aldol reactions performed in wet solvent‐free conditions |
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Authors: | Gabriela Huelgas,Ratnasamy Somanathan,Julio M. Hern ndez P rez,Haydee Rojas Cabrera,Maximiliano de la Higuera Mací as,Alejandra Domí nguez‐Huerta,Rocí o Sabala,Cecilia Anaya de Parrodi |
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Affiliation: | Gabriela Huelgas,Ratnasamy Somanathan,Julio M. Hernández Pérez,Haydee Rojas Cabrera,Maximiliano de la Higuera Macías,Alejandra Domínguez‐Huerta,Rocío Sabala,Cecilia Anaya de Parrodi |
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Abstract: | 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. |
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Keywords: | 1,2‐diamines aldol reaction asymmetric organocatalysis bifunctional prolinamides C2‐symmetry axis stereoselectivity wet solvent‐free |
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