RESUMEN
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.
RESUMEN
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).
Asunto(s)
Pargilina/análogos & derivados , Propilaminas/síntesis química , Agua/química , Aldehídos/química , Alquinos/química , Aminas/química , Catálisis , Cobre/química , Pargilina/síntesis química , Pargilina/química , Propilaminas/química , EstereoisomerismoRESUMEN
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.
RESUMEN
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.