Enantioselective Direct Mannich Reactions of Cyclic β‑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 β-ketoesters and <i>N</i>-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

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

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