Title:Chiral Thiazolidine based Organocatalysts: Synthesis and Application in Asymmetric Aldol Reactions
VOLUME: 17 ISSUE: 5
Author(s):Ana Rita G. Félix, Pedro R.D. Simões, Francisco J.P.M. Sousa, M. Elisa Silva Serra and Dina Murtinho*
Affiliation:CQC, Department of Chemistry, University of Coimbra, Coimbra, CQC, Department of Chemistry, University of Coimbra, Coimbra, CQC, Department of Chemistry, University of Coimbra, Coimbra, CQC, Department of Chemistry, University of Coimbra, Coimbra, CQC, Department of Chemistry, University of Coimbra, Coimbra
Keywords:Thiazolidines, organocatalyst, aldol reaction, enantioselective, asymmetric synthesis, additives.
Abstract:Several novel chiral organocatalysts derived from thiazolidines containing amide and thioureia
functionalities were synthesized in good yields. These organocatalysts were tested in the asymmetric
aldol reaction of acetone with p-nitrobenzaldehyde. Reaction parameters such as reaction time, catalyst
loading and solvent were optimized. Products with conversions up to 84% and enantiomeric ratios
(er) up to 84.5:15.5 (R:S) were obtained. The effect of several chiral and non-chiral additives on the
reactivity and selectivity of the reaction was also evaluated. The reaction was extended to other aromatic
aldehydes with the best organocatalyst and when p-bromobenzaldehyde was used, an er of
94.5:5.5 (R:S) was obtained.