Zhenyuan Xu

A novel synthesis of fluorinated pyrazoles via gold(I)-catalyzed tandem aminofluorination of alkynes in the presence of Selectfluor.

A mild and efficient protocol for the synthesis of fluorinated pyrazoles has been developed via gold(I)-catalyzed tandem aminofluorination of alkynes in the presence of Selectfluor. This method offers a broad substrate scope.

Palladium-Catalyzed Chelation-Assisted Aromatic C–H Nitration: Regiospecific Synthesis of Nitroarenes Free from the Effect of the Orientation Rules

A palladium-catalyzed chelation-assisted ortho-nitration of aryl C-H bond is described. A range of azaarenes such as 2-arylquinoxalines, pyridines, quinoline, and pyrazoles were nitrated with excellent chemo- and regioselectivity. Using the O-methyl oximyl group as a removable directing group, the regiospecific synthesis of a variety of o-nitro aryl ketones was achieved starting from aryl ketones via a three-step process involving the Pd-catalyzed ipso-nitration of C-H bond as a key step. Mechanistic investigations support a silver-mediated radical mechanism involving Pd((II/III) and/or Pd(II/IV) catalytic cycles under oxidizing conditions.

Gold(III)-catalyzed tandem conjugate addition/annulation of 4-hydroxycoumarins with α,β-unsaturated ketones.

An efficient and selective approach for the synthesis of functionalized pyranocoumarins has been developed via a gold(III)-catalyzed tandem conjugate addition/annulation reaction of 4-hydroxycoumarins with α,β-unsaturated ketones.

Gold(III)-Catalyzed Tandem Reaction of Ketones with Phenols: Efficient and Highly Selective Synthesis of Functionalized 4H-Chromenes

An efficient and highly selective approach for the synthesis of functionalized 4H-chromenes has been developed via gold(III)-catalyzed condensation/annulation tandem reaction of ketones with phenols.

Gold(III)-Catalyzed Tandem Reaction of O-Arylhydroxylamines with 1,3-Dicarbonyl Compounds: Highly Selective Synthesis of 3-Carbonylated Benzofuran Derivatives

A highly regioselective protocol for the synthesis of 3-carbonylated benzofuran derivatives has been developed involving the gold(III)-catalyzed tandem condensation/rearrangement/cyclization reaction of O-arylhydroxylamines with 1,3-dicarbonyl compounds.

Gold(I)-catalyzed synthesis of 1,5-benzodiazepines directly from o-phenylenediamines and alkynes.

A unique gold(I)-catalyzed highly atom-economic synthesis of 1,5-benzodiazepines directly from o-phenylenediamines and alkynes has been achieved for the first time.

Gold-Catalyzed Simultaneous Formation of C-C, C=O, and C-F bonds in the Presence of Selectfluor: A Synthesis of Fluoroindenes from Allene Esters

An approach for the synthesis of fluorinated indene derivatives has been developed via a gold-catalyzed three-component tandem reaction between allene esters, Selectfluor, and water.

Copper-Catalyzed Oxidative Cyclization of 1,5-Enynes with Concomitant C-C Bond Cleavage: An Unexpected Access to 3-Formyl-1-indenone Derivatives

A Cu(0)/Selectfluor system-mediated oxidative cyclization of 1,5-enynes with concomitant C-C bond cleavage to access 3-formyl-1-indenone derivatives is described. Preliminary mechanistic investigations disclosed that the C-C bond cleavage involved a novel water-participated oxygen-insertion β-carbon elimination through double oxycuprations.

Multifold bond cleavage and formation between MeOH and quinoxalines (or benzothiazoles): synthesis of carbaldehyde dimethyl acetals.

A K(2)S(2)O(8)-mediated direct cross-coupling of quinoxalines (or benzothiazoles) with methanol leading to 2-quinoxalinyl (or 2-benzothiazolyl) carbaldehyde dimethyl acetals has been achieved. 2-Quinoxalinyl carbaldehyde dimethyl acetals were readily converted into 2-quinoxalinyl carbaldehydes in good to excellent yields under acidic conditions. Preliminary mechanistic studies suggest that the reaction proceeds via multifold bond cleavage and formation between methanol and N-heterocycles involving a dioxygen-participated radical process. This method allows for the synthesis of a variety of 2-quinoxalinyl (or 2-benzothiazolyl) carbaldehyde dimethyl acetals directly via cross-coupling of simple N-heterocyclic C-H bond and methanol under aldehyde-, acid-, and transition-metal-free conditions.

Prolinethiol ether catalysis in an asymmetric Michael reaction: solvent-free synthesis of functionalized monohaloalkenes.

The organocatalytic Michael reaction of ketones with γ-monohalonitrodienes catalyzed by chiral prolinethiol ether under solvent-free conditions was developed. The described method represents a novel approach for accessing highly functionalized monohaloalkenes with α, β-stereocenters of up to >99% ee.