The synthesis of a new, highly efficient cis-ion-tagged catalyst (8a), possessing an amide linkage between the imidazolium tag and the proline ring, is described. This new bench-stable catalyst has been tested in the classic asymmetric aldol condensation between ketones and aldehydes "in the presence" of water, and is proposed as a valuable alternative to the analogous but more sensitive ester cis-2d. Catalyst 8a displayed an excellent efficiency in terms of catalyst loading and stereochemical control.
E. Montroni, S. P. Sanap, M. Lombardo, A. Quintavalla, C. Trombini, D. D. Dhavale (2011). A New Robust and Efficient Ion-Tagged Proline Catalyst Carrying an Amide Spacer, for the Asymmetric Aldol Reaction. ADVANCED SYNTHESIS & CATALYSIS, 353, 3234-3240 [10.1002/adsc.201100595].
A New Robust and Efficient Ion-Tagged Proline Catalyst Carrying an Amide Spacer, for the Asymmetric Aldol Reaction
MONTRONI, ELISA;LOMBARDO, MARCO;QUINTAVALLA, ARIANNA;TROMBINI, CLAUDIO;
2011
Abstract
The synthesis of a new, highly efficient cis-ion-tagged catalyst (8a), possessing an amide linkage between the imidazolium tag and the proline ring, is described. This new bench-stable catalyst has been tested in the classic asymmetric aldol condensation between ketones and aldehydes "in the presence" of water, and is proposed as a valuable alternative to the analogous but more sensitive ester cis-2d. Catalyst 8a displayed an excellent efficiency in terms of catalyst loading and stereochemical control.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
