RESUMO
Organocatalytic enantioselective aza-Friedel-Crafts reactions of cyclic ketimines with pyrroles or indoles were catalyzed by imidazoline/phosphoric acid catalysts. The reaction was applied to various 3H-indol-3-ones to afford products in excellent yields and enantioselectivities. The chiral catalysts can be recovered by a single separation step using column chromatography and are reusable without further purification. Based on the experimental investigations, a possible transition state has been proposed to explain the origin of the asymmetric induction.
RESUMO
Highly enantioselective desymmetrization of aziridines with TMSNCS has been developed. Good yield and enantioselectivity were observed by using novel chiral imidazoline-phosphoric acid catalysts. The obtained product can be converted to a chiral ß-aminothiol and a ß-aminosulfonic acid.
RESUMO
An enantioselective three-component reaction of aldehydes, amines, and alkynes in water by using a bis(imidazoline)-Cu(I) catalysts having a hydrophobic substituent and sodium dodecyl sulfate as a surfactant was developed. The reaction was applied to a broad range of aldehydes and alkynes to give optically active propargylamines with excellent yields (up to 99 %) and enantiomeric excesses (up to 99 %â ee).
Assuntos
Pargilina/análogos & derivados , Propilaminas/síntese química , Água/química , Aldeídos/química , Alcinos/química , Aminas/química , Catálise , Cobre/química , Pargilina/síntese química , Pargilina/química , Propilaminas/química , EstereoisomerismoRESUMO
An organocatalytic enantioselective Mannich-type reaction of isocyanoacetate with N-sulfonylimines catalyzed by chiral thioureas derived from quinine yielded 2-imidazolines with high diastereo- and enantioselectivities (up to >99:1 dr. and 96% ee). This reaction provided a convenient route to access various imidazolines and related α,ß-diamino acids having a quaternary carbon center in high enantiomeric purities.
