Cocatalytic Activity of the Furfuryl and Oxanorbornane-Substituted Guanidines in the Aldol Reaction Catalyzed by (S)-Proline.
Int J Mol Sci
; 25(10)2024 May 20.
Article
em En
| MEDLINE
| ID: mdl-38791607
ABSTRACT
This work investigated the cocatalytic activity of recently prepared guanidinium salts containing an oxanorbornane subunit in an (S)-proline-catalyzed aldol reaction. The activity was interpreted by the diastereoselectivity of the reaction (anti/syn ratio) and for the most interesting polycyclic guanidinium salt, the enantioselectivity of the reaction was determined. The results indicated a negative impact on the oxanorbornane unit if present as the flexible substituent. For most of the tested aldehydes, the best cocatalysts provided enantioselectivities above 90% and above 95% at room temperature and 0 °C, respectively, culminating in >99.5% for 4-chloro- and 2-nitrobenzaldehyde as the substrate. The barriers for forming four possible enantiomers were calculated and the results for two anti-enantiomers are qualitatively consistent with the experiment. Obtained results suggest that the representatives of furfurylguanidinium and rigid polycyclic oxanorbornane-substituted guanidinium salts are good lead structures for developing new cocatalysts by tuning the chemical space around the guanidine moiety.
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Texto completo:
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Base de dados:
MEDLINE
Assunto principal:
Prolina
/
Guanidinas
Idioma:
En
Ano de publicação:
2024
Tipo de documento:
Article