Catalytic Enantioselective Ring-Opening and Ring-Closing Reactions of 3‑Isothiocyanato Oxindoles and <i>N</i>‑(2-Picolinoyl)aziridines

3-Isothiocyanato oxindoles have been successfully applied to an asymmetric formal [3 + 3] cycloaddition reaction with aziridines for the first time. The reaction was efficiently mediated by an in situ generated magnesium catalyst employing (<i>R</i>)-3,3′-fluorous-BINOL as a simple chiral ligand. Serials of polycyclic frameworks could be obtained after a ring-closing step. The enantioenriched ring-opening product was also utilized to modified amino acids, peptides, and bifunctional organocatalyst

Catalytic Enantioselective Ring-Opening and Ring-Closing Reactions of 3‑Isothiocyanato Oxindoles and <i>N</i>‑(2-Picolinoyl)aziridines

3-Isothiocyanato oxindoles have been successfully applied to an asymmetric formal [3 + 3] cycloaddition reaction with aziridines for the first time. The reaction was efficiently mediated by an in situ generated magnesium catalyst employing (<i>R</i>)-3,3′-fluorous-BINOL as a simple chiral ligand. Serials of polycyclic frameworks could be obtained after a ring-closing step. The enantioenriched ring-opening product was also utilized to modified amino acids, peptides, and bifunctional organocatalyst

Catalytic Desymmetrization of <i>meso</i>-Aziridines with Benzofuran-2(3<i>H</i>)‑Ones Employing a Simple In Situ-Generated Magnesium Catalyst

The first example of catalytic desymmetrization of <i>meso</i>-aziridines with benzofuran-2­(3<i>H</i>)-ones is realized by employing a magnesium catalyst utilizing BINOL as a simple and commercially available chiral ligand. Both of the enantiomers of the ring-opening product could be easily accessed by employing (<i>R</i>)- or (<i>S</i>)-BINOL as chiral ligand, respectively. A variety of enantioenriched 3,3-disubstituted benzofuran-2­(3<i>H</i>)-ones containing multiple linear continuous stereocenters were obtained with moderate to good yields, diastereo- and enantioselectivities

Development and Application of α‑Heteroatom Ketones in Asymmetric Michael Reaction with β-<i>trans</i>-Nitroalkenes

The successful design and application of a new type of <i>N</i>-phenyl-imidazole-modified α-heteroatom ketones in asymmetric <i>anti</i>-selective Michael reactions with β-<i>trans</i>-nitroalkenes is reported. High yields and enantioselectivities could be obtained, and the corresponding conjugate adducts could be further transformed into related chiral esters and cyclopropane derivatives with excellent enantioselectivities

Concerted Enantioselective [2+2] Cycloaddition Reaction of Imines Mediated by a Magnesium Catalyst

Enantioselective [2 + 2] cyclization between an imine and a carbon–carbon double bond is a versatile strategy to build chiral azetidines. However, α-branched allenoates have never been successfully applied in [2 + 2] cyclization reactions with imines, as they always undergo Kwon’s [4 + 2] annulation in previous catalytic methods. Herein, a simple in situ generated magnesium catalyst was employed to successfully achieve the enantioselective [2 + 2] cyclization reaction of DPP-imines and α-branched allenoates for the first time. Insightful experiments including KIE experiments, controlled experiments, Hammett plot analysis, and 31P NMR studies of initial intermediates indicate that the current [2 + 2] cyclization of imine most likely involves an asynchronous concerted transition state. Further mechanistic investigations by combining kinetic studies, ESI experiments, 31P NMR studies of coordination complexes, and controlled experiments on reaction rates under different catalyst loading amounts provided the coordination details for this [2 + 2] cyclization reaction between DPP-imines and α-branched allenoates. This new approach was applied to the synthesis of various chiral aza-heterocycles, including the enantioselective synthesis of the key intermediate of a lipid-lowering agent Ezetimibe

Magnesium Catalysis Mediated Tetrazoles in Desymmetrization Reaction of Aziridines

A magnesium-catalyzed asymmetric ring-opening reaction of aziridines with substituted tetrazoles is reported. The current protocol proceeds smoothly and gives the corresponding desymmetrization products in high yields and good enantioselectivities. A new chiral ligand was synthesized from azetidine and (<i>R</i>)-BINOL and was employed in the current in situ generated magnesium catalyst. The Mg­(II)-mediated desymmetrization reaction could be performed on gram scale under mild conditions and was transformed to chiral alkyl amines by a deprotection process

Catalytic Asymmetric [3 + 2] Cyclization Reactions of 3‑Isothiocyanato Oxindoles and Alkynyl Ketones Via an in Situ Generated Magnesium Catalyst

A highly enantioselective formal [3 + 2] cycloaddition reaction between 3-isothiocyanato oxindoles and alkynyl ketones is reported for the first time. An oxazoline–OH type chiral ligand derived from <i>o</i>-hydroxy-phenylacetic acid is employed to generate an effective magnesium catalyst in the current cyclization reaction and give serials of chiral spirooxindoles with good chemical yields and enantioselectivities

Correction to “Nickel-Mediated Asymmetric Allylic Alkylation between Nitroallylic Acetates and Acyl Imidazoles”

Correction to “Nickel-Mediated Asymmetric Allylic Alkylation between Nitroallylic Acetates and Acyl Imidazoles

Correction to “Nickel-Mediated Asymmetric Allylic Alkylation between Nitroallylic Acetates and Acyl Imidazoles”

Correction to “Nickel-Mediated Asymmetric Allylic Alkylation between Nitroallylic Acetates and Acyl Imidazoles

Development of ProPhenol/Ti(IV) Catalyst for Asymmetric Hydroxylative Dearomatization of Naphthols

By development of ProPhenol/Ti(IV) catalysts, a catalytic enantioselective hydroxylative dearomatization of naphthols is achieved by using TBHP as a simple oxidative reagent. The side coordinative chain equipped on the C1-position of β-naphthols plays an important role for initiating this asymmetric hydroxylative reaction, which might be a result of the proper cocoordination effects to the titanium center in the catalyst. A reasonable catalytic cycle is proposed, the catalytic system is applied to a reasonable range of this type of phenolic compound, and related concise transformations are carried out