Base-catalyzed controllable reaction of 3-ylideneoxindoles with O-Boc hydroxycarbamates for the synthesis of amidoacrylates and spiroaziridine oxindoles.

A base-catalyzed divergent reaction of 3-ylideneoxindoles with O-Boc hydroxycarbamates has been developed to provide efficient access to various amidoacrylates and spiroaziridine oxindoles with generally high yields, which should be potentially useful in drug discovery.

Synthesis of CF3-containing 3,3'-cyclopropyl spirooxindoles by sequential [3 + 2] cycloaddition/ring contraction of ylideneoxindoles with 2,2,2-trifluorodiazoethane.

A [3 + 2] cycloaddition/ring contraction sequence of ylideneoxindoles with in situ-generated 2,2,2-trifluorodiazoethane without the use of any transition-metal catalyst has been developed. The reaction provides efficient access to biologically important and synthetically useful CF3-containing 3,3'-cyclopropyl spirooxindoles in high yield (74-99%) with high diastereoselectivity (>95:5 d.r.).

An organocatalytic Michael-aldol cascade: formal [3+2] annulation to construct enantioenriched spirocyclic oxindole derivatives.

An efficient organocatalytic Michael-aldol cascade reaction for the asymmetric synthesis of spirocyclic oxindole derivatives fused with tetrahydrothiophenes has been developed through a formal [3+2] annulation strategy.

Facile synthesis of enantioenriched Cγ-tetrasubstituted α-amino acid derivatives via an asymmetric nucleophilic addition/protonation cascade.

An asymmetric nucleophilic addition/protonation reaction of 3-substituted oxindoles and ethyl 2-phthalimidoacrylate has been described. This strategy can give direct access to C(γ)-tetrasubstituted α-amino acid derivatives bearing 1,3-nonadjacent stereocenters with up to 98% yield, 94:6 dr, and >99% ee. Dual activation is proposed in the transition state, and the opposite enantiomers can be obtained simply by changing cinchonidine-derived catalyst to the cinchonine analogue.

Enantioselective conjugate addition of oximes to trisubstituted ß-nitroacrylates: an organocatalytic approach to ß(2,2)-amino acid derivatives.

A highly enantioselective organocatalytic intermolecular conjugate addition of oximes to ß-nitroacrylates has been developed. The highly functionalized adducts obtained are valuable precursors for asymmetric synthesis, as demonstrated by the synthesis of ß(2,2)-amino acids and oxazolidin-2-ones.

Enantioselective Michael reactions of beta, beta-disubstituted nitroalkenes: a new approach to beta(2,2)-amino acids with hetero-quaternary stereocenters.

An atom-economic organocatalytic asymmetric Michael reaction of alpha,beta,beta-trisubstituted olefins has been successfully developed. The reaction exhibits excellent enantioselectivities under low loading of catalysts, and the conjugate addition products are valuable for the synthesis of novel beta(2,2)-amino acids and beta-peptides.