Proline-based organocatalyst-mediated asymmetric aldol reaction of acetone with substituted aromatic aldehydes: an experimental and theoretical study

Authors

NEVİN ARSLAN
SELAMİ ERCAN
NECMETTİN PİRİNÇÇİOĞLU

Abstract

This work involves a facile synthesis of three (S)-proline-based organocatalysts with C$_{2}$ symmetry and their effects in enantioselective aldol reaction of acetone with substituted aromatic aldehydes. Moderate enantioselectivities (up to 61% ee) were obtained depending on the nature of the substituents on the aryl ring. Computational calculations at HF/6-31 + G(d) level were employed to underline the enantioselectivity imposed by all the organocatalysts. Higher calculations at B3LYP/6-311 ++ G(d,p) scrf=(solvent=dichloromethane)//B3LYP/6-31 + G(d) levels of theory were also performed for the aldol reaction of acetone with benzaldehyde and 4-nitrobenzaldehyde catalyzed by 1. The computationaloutcomeswereconsistentwiththoseproducedbyexperimentalresultsandtheywerevaluabletoelucidate the mechanism for the observed stereoselectivity.

DOI

10.3906/kim-1908-3

Keywords

Acetone, aldol reaction, computational modelling, enantioselectivity, organocatalysis, proline, substituted aldehydes

First Page

335

Last Page

351

Recommended Citation

ARSLAN, NEVİN; ERCAN, SELAMİ; and PİRİNÇÇİOĞLU, NECMETTİN (2020) "Proline-based organocatalyst-mediated asymmetric aldol reaction of acetone with substituted aromatic aldehydes: an experimental and theoretical study," Turkish Journal of Chemistry: Vol. 44: No. 2, Article 6. https://doi.org/10.3906/kim-1908-3
Available at: https://journals.tubitak.gov.tr/chem/vol44/iss2/6