Bifunctional Quaternary Ammonium Salts Catalyzed Stereoselective Conjugate Addition of Oxindoles to Electron-Deficient ß-Haloalkenes.

A highly Z-selective asymmetric conjugate addition of 3-substituted oxindoles to ß-haloalkene ketones/esters catalyzed by readily available chiral bifunctional quaternary ammonium salts is reported. This reaction provides efficient access to a range of 2-oxoindole derivatives bearing a thermodynamically unstable Z-olefin structure and a chiral quaternary carbon center in high yields (up to 90%) and with good to high stereoselectivities (up to >19:1 Z/E and 91% ee) under mild conditions.

Total Synthesis of Gelsedilam by Means of a Thiol-Mediated Diastereoselective Conjugate Addition-Aldol Reaction.

The total synthesis of gelsedilam, which features a highly diastereoselective thiol conjugate addition-intramolecular aldol reaction to install the strained and caged [3.2.2] bridged ring system and highly efficient NiCl2 /NaBH4 -mediated four-step transformation in one-pot to construct its five-membered lactam ring is reported. The synthesis requires only 18 linear steps from the known compounds, providing useful strategies for the construction of the intricate ring system in the synthesis of related gelsedine-type alkaloids.

Asymmetric α-amination of 3-substituted oxindoles using chiral bifunctional phosphine catalysts.

A highly enantioselective α-amination of 3-substituted oxindoles with azodicarboxylates catalyzed by amino acids-derived chiral phosphine catalysts is reported. The corresponding products containing a tetrasubstituted carbon center attached to a nitrogen atom at the C-3 position of the oxindole were obtained in high yields and with up to 98% ee.

Palladium(II)-Catalyzed Formal [3 + 2] Cycloaddition of Aziridines with 3-Substituted Indoles: Synthesis of Enantioenriched Pyrroloindolines.

A Pd-catalyzed enantiospecific formal [3 + 2] cycloaddition between chiral aziridines and indoles has been developed. With this method, chiral pyrroloindolines in enantiomerically pure forms were constructed in high yields and diastereoselectivities under mild conditions.

Thiourea-Quaternary Ammonium Salt Catalyzed Asymmetric 1, 3-Dipolar Cycloaddition of Imino Esters To Construct Spiro[pyrrolidin-3,3'-oxindoles].

A highly enantioselective 1,3-dipolar cycloaddition of imino esters with methyleneindolinones has been realized by using readily available thiourea-quaternary ammonium salts as phase-transfer catalysts, enabling efficient construction of a range of chiral spiro[pyrrolidin-3,3'-oxindoles] in good yields with excellent enantioselectivities under mild conditions.

Enantioselective direct Mannich reactions of cyclic ß-ketoesters catalyzed by chiral phosphine via a novel dual-reagent catalysis.

A combination of an amino acid derived chiral phosphine catalyst and methyl acrylate efficiently catalyzed the direct Mannich reaction of cyclic ß-ketoesters and N-Boc-aldimines. The dual-reagent catalysis was presumed to function through the formation of a zwitterion, which catalyzed the reaction with excellent stereocontrol via a hydrogen-bonding assisted chiral ion-pair pathway.