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Chiral ionic liquids based on L-cysteine derivatives for asymmetric aldol reaction
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Orientador(es)
Resumo(s)
Structure, and consequently properties, of ionic liquids can be easily tailored by changing cation/anion combinations and/or attaching functional groups. By grafting enantiopure moieties to the framework of ionic liquid it is possible to prepare bioinspired chiral molecules that can serve as a reaction medium, additive or even asymmetric catalyst. In this context, new chiral ionic liquids (CILs), based on biomolecules, such as aminoacids (L-cysteine derivatives), have been synthesised and tested in asymmetric aldol condensation of aldehydes and ketones. The best results were obtained for CILs composed of S-methyl-L-cysteine cation and bis(trifluoromethane)sulfonimide anion, in the reaction of 2-or 4-nitrobenzaldehyde with acetone or cyclohexanone, giving the aldol product in moderate yields 70–76% and high ee values (up to 96%).
Descrição
POCI-01-0145-FEDER–007265
PTDC/QUI-QOR/32406/2017
022161
Palavras-chave
Aldol reactions Asymmetric catalysis Chiral ionic liquids Cysteine derivatives Organocatalysts Catalysis Physical and Theoretical Chemistry