Organocatalytic asymmetric Michael addition of unprotected 3-substituted oxindoles to 1,4-naphthoquinone
نویسندگان
چکیده
We reported the first example of organocatalytic Michael addition of unprotected 3-prochiral oxindoles 1 to 1,4-naphthoquinone. Quinidine derivative (DHQD)(2)PYR was found to be able to catalyze this reaction in up to 83% ee, with moderate to excellent yields. This method could be used for the synthesis of enantioenriched 3,3-diaryloxindoles, and the catalytic synthesis of which was unprecedented.
منابع مشابه
Asymmetric construction of quaternary stereocenters by direct organocatalytic amination of 3-substituted oxindoles.
Quinidine derivative (QD)(2)PYR was found to catalyze the asymmetric direct amination of unprotected prochiral 3-oxindole with DIAD to construct quaternary stereocenters at the C3 position with excellent enantioselectivity.
متن کاملDioxindole in asymmetric catalytic synthesis: direct access to 3-substituted 3-hydroxy-2-oxindoles via 1,4-additions to nitroalkenes.
The asymmetric Michael addition of dioxindoles to β-substituted nitroalkenes is reported. The bifunctional primary amine-thiourea A, by means of a non-covalent-based mode of catalysis, secures direct access to 3-substituted 3-hydroxyoxindole derivatives with high stereocontrol.
متن کاملEnantioselective conjugate addition of 3-fluoro-oxindoles to vinyl sulfone: an organocatalytic access to chiral 3-fluoro-3-substituted oxindoles.
An organocatalytic conjugate addition of prochiral 3-fluorinated oxindoles to vinyl sulfones was described for the first time. In the presence of bifunctional tertiary amine-thiourea catalysts, 3-fluoro-3-substituted oxindole adducts were obtained in excellent yields and with high enantiomeric excesses.
متن کاملEnantioselective organocatalytic oxyamination of unprotected 3-substituted oxindoles.
An enantioselective α-oxyamination of unprotected 3-substituted oxindoles with nitrosobenzene catalyzed by tertiary amine-thiourea bifunctional organocatalysts has been developed and affords the corresponding 3-amino-2-oxindole derivatives in good yields and with moderate to excellent enantioselectivities (up to > 99.9 : 0.1 er when the product is isolated by direct filtration from the reaction...
متن کاملCatalytic asymmetric desymmetrization of N-arylmaleimides: efficient construction of both atom chirality and axial chirality.
The catalytic asymmetric Michael addition/desymmetrization reaction of N-(2-t-butylphenyl)maleimides with unprotected 3-substituted-2-oxindoles was successfully realized using a chiral N,N'-dioxide-Sc(III) complex, leading to succinimides with two kinds of stereogenic elements—atom chirality and axial chirality—in up to 99% yield, 99% ee and >19 : 1 d.r.
متن کامل