We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Remote Substituent Effects on the Stereoselectivity and Organocatalytic Activity of Densely Substituted Unnatural Proline Esters in Aldol Reactions.
- Authors
de Gracia Retamosa, María; de Cózar, Abel; Sánchez, Mirian; Miranda, José I.; Sansano, José M.; Castelló, Luis M.; Nájera, Carmen; Jiménez, Ana I.; Sayago, Francisco J.; Cativiela, Carlos; Cossío, Fernando P.
- Abstract
The organocatalytic activities of highly substituted proline esters obtained through asymmetric [3+2] cycloadditions of azomethine ylides derived from glycine iminoesters have been analyzed by 19F NMR and through kinetic isotope effects. Kinetic rate constants have been determined for unnatural proline esters incorporating different substituents. It has been found that exo- L and endo- L unnatural proline methyl esters yield opposite enantiomers in aldol reactions between cyclic ketones and aromatic aldehydes. The combined results reported in this study show subtle and remote effects that determine the organocatalytic behavior of these synthetic but readily available amino acid derivatives. These data can be used as design criteria for the development of new pyrrolidine-based organocatalysts.
- Subjects
ESTERS; ORGANOCATALYSIS; RING formation (Chemistry); YLIDES; KINETIC isotope effects; ENANTIOMERS
- Publication
European Journal of Organic Chemistry, 2015, Vol 2015, Issue 11, p2503
- ISSN
1434-193X
- Publication type
Article
- DOI
10.1002/ejoc.201500160