Cocatalytic Activity of the Furfuryl and Oxanorbornane-Substituted Guanidines in the Aldol Reaction Catalyzed by (S)-Proline

Barešić, Luka; Marijanović, Monika; Dokli, Irena; Margetić, Davor; Glasovac, Zoran (2024) Cocatalytic Activity of the Furfuryl and Oxanorbornane-Substituted Guanidines in the Aldol Reaction Catalyzed by (S)-Proline. International Journal of Molecular Sciences, 25 (10). ISSN 1422-0067

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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.

Item Type:	Article
Uncontrolled Keywords:	oxanorbornane; guanidinium salt; (S)-proline; aldol reaction; diastereoselectivity; enantioselectivity; DFT calculations
Subjects:	NATURAL SCIENCES > Chemistry > Organic Chemistry
Divisions:	Division of Organic Chemistry and Biochemistry NMR Center
Projects:	Project title Project leader Project code Project type Cikloadicijske strategije prema policikličkim gvanidinima-CycloGu Davor Margetić IP-2018-01-3298 HRZZ Prostorne modulacije gvanidina Davor Margetić IP-2022-10-4385 Znanstveno-istraživački projekti
Depositing User:	Lorena Palameta
Date Deposited:	15 Oct 2024 14:28
URI:	http://fulir.irb.hr/id/eprint/9168
DOI:	10.3390/ijms25105570

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