Resumen

MEJIA-NUNEZ, Dulce M.; MASTACHI-LOZA, Salvador; MARTINEZ-OTERO, Diego  y  ROMERO-ORTEGA, Moisés. 4(S)-Benzyl-1,3-thiazolidin-2-one a Novel Chiral Auxiliary for Asymmetric Aldol Coupling through Titanium Enolates. J. Mex. Chem. Soc [online]. 2024, vol.68, n.1, pp.144-155.  Epub 24-Mar-2025. ISSN 1870-249X.  https://doi.org/10.29356/jmcs.v68i1.2067.

The chlorotitanium enolate of N-propionyl-4(S)-benzyl-1,3-thiazolidin-2-one, was condensed with aryl aldehydes, in good diastereoselectivity to give the ‘Evans syn’ aldol (73:27 - 97:3), using equimolar amounts of titanium tetrachloride (1.5 equiv), and N,N-diisopropylethylamine (DIPEA). The facial selectivity in the aldol additions probably involves a non-chelated transition state. In all aldol reactions, the presence of a minor product, the ‘non-Evans syn’ aldol, was obtained and confirmed by X-ray diffraction analysis of a single-crystal compound containing the mixture of diastereoisomers. The chiral auxiliary in these 1,3-thiazolidin-2-one aldol derivatives can be easily removed by nucleophilic species through acyl substitution.

Palabras llave : Chiral auxiliaries; coupling reaction; stereoselective synthesis; aldol adducts; thiazolidinone.

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