Chaorong Qi

Copper-Catalyzed Aerobic Oxidative NS Bond Functionalization for CS Bond Formation: Regio- and Stereoselective Synthesis of Sulfones and Thioethers

A regio- and stereoselective synthesis of sulfones and thioethers by means of Cu(I)-catalyzed aerobic oxidative N-S bond cleavage of sulfonyl hydrazides, followed by cross-coupling reactions with alkenes and aromatic compounds to form the C sp 2-S bond, is described herein. N2 and H2O are the byproducts of this transformation, thus offering an environmentally benign process with a wide range of potential applications in organic synthesis and medicinal chemistry.

TBHP/I2-mediated domino oxidative cyclization for one-pot synthesis of polysubstituted oxazoles.

A facile type of one-pot, transition-metal-free domino process was developed for the synthesis of oxazoles. Thus, a variety of polysubstituted oxazoles were easily synthesized via t-BuOOH/I(2)-mediated domino oxidative cyclization from readily available starting materials under mild conditions.

Copper-catalyzed intermolecular oxidative [3 + 2] cycloaddition between alkenes and anhydrides: a new synthetic approach to γ-lactones.

A new copper-catalyzed oxidative [3 + 2] cycloaddition of alkenes with anhydrides using oxygen as the sole oxidant to afford γ-lactones has been developed. This catalyzed cyclization process has a broad substrate scope and affords γ-lactones in good to excellent yields.

Base‐Promoted Coupling of Carbon Dioxide, Amines, and N‐Tosylhydrazones: A Novel and Versatile Approach to Carbamates

A base-promoted three-component coupling of carbon dioxide, amines, and N-tosylhydrazones has been developed. The reaction is suggested to proceed via a carbocation intermediate and constitutes an efficient and versatile approach for the synthesis of a wide range of organic carbamates. The advantages of this method include the use of readily available substrates, excellent functional group tolerance, wide substrate scope, and a facile work-up procedure.

Synthetic approach to polysubstituted furans: an efficient addition/oxidative cyclization of alkynoates and 1,3-dicarbonyl compounds.

A novel and reliable method for the direct construction of polysubstituted furans is reported. The key transformation involves Sn(II)- and Cu(I)-involved addition/oxidative cyclization of alkynoates and 1,3-dicarbonyl compounds in the presence of 2,3-dichloro-5,6-dicyanobenzoquinone.

Silver-Catalyzed Difunctionalization of Terminal Alkynes: Highly Regio- and Stereoselective Synthesis of (Z)-β-Haloenol Acetates

A new silver-catalyzed highly regio- and stereoselective difunctionalization reaction of simple terminal alkynes was reported in which the (Z)-beta-haloenol acetate derivatives were formed efficiently. The resulting products were versatile intermediates in organic synthesis.

Ni(salphen)-based metal–organic framework for the synthesis of cyclic carbonates by cycloaddition of CO2 to epoxides

A well-defined homogeneous molecular catalyst Ni(salphen) was introduced as a “metalloligand” in a MOF, providing an efficient and recyclable heterogeneous catalyst for the synthesis of cyclic carbonates by the cycloaddition of CO2 to epoxides under relatively mild conditions.

A chiral mixed metal–organic framework based on a Ni(saldpen) metalloligand: synthesis, characterization and catalytic performances

A three-dimensional (3D) chiral mixed metal-organic framework [Cd4Cl(Ni-L)3(Ni-HL)(H2O)6(DMF)]·4DMF (CMOF 1) based on a new enantiopure dicarboxyl-functionalized Ni(saldpen) metalloligand Ni-H2L and a novel tetranuclear cadmium cluster [Cd4Cl(CO2)7(CO2H)] has been synthesized and characterized by elemental analyses, IR and UV-vis spectra, thermogravimetric analysis, nitrogen and carbon dioxide adsorption, powder and single-crystal X-ray diffractions. Each tetranuclear-cadmium cluster in 1 is linked by eight Ni-L ligands, and each Ni-L ligand is linked by two tetranuclear-cadmium clusters to generate a 3D framework with 1D open channels (∼1.1 × 0.9 nm(2)) along the b-axis. Based on its good stability, permanent porosity, Lewis acid sites and moderate uptake for CO2, 1 can be used as a self-supported heterogeneous catalyst for the synthesis of optically active propylene carbonate by asymmetric cycloaddition of CO2 with racemic propylene oxide under relatively mild conditions.

Nano‐Cu2O‐Catalyzed Formation of CC and CO Bonds: One‐Pot Domino Process for Regioselective Synthesis of α‐Carbonyl Furans from Electron‐Deficient Alkynes and 2‐Yn‐1‐ols

The formation of carbon-carbon and carbon-oxygen bonds continues to be an active and challenging field of chemical research. Nanoparticle catalysis has attracted considerable attention owing to its environmentally benign and high activity toward the reactions. Herein, we described a novel and effective nano-Cu(2)O-catalyzed one-pot domino process for the regioselective synthesis of α-carbonyl furans. Various electron-deficient alkynes with 2-yn-1-ols underwent this process smoothly in moderate to good yields in the presence of air at atmospheric pressure. It is especially noteworthy that a novel 2,4,5-trisubstituted 3-ynylfuran was formed in an extremely direct manner without tedious stepwise synthesis. Additionally, as all of the starting materials are readily available, this method may allow the synthesis of more complex α-carbonyl furans. An experiment to elucidate the mechanism suggested that the process involved a carbene intermediate.

Copper-catalyzed aerobic oxidative transformation of ketone-derived N-tosyl hydrazones: an entry to alkynes.

A novel strategy involving Cu-catalyzed oxidative transformation of ketone-derived hydrazone moiety to various synthetic valuable internal alkynes and diynes has been developed. This method features inexpensive metal catalyst, green oxidant, good functional group tolerance, high regioselectivity and readily available starting materials. Oxidative deprotonation reactions were carried out to form internal alkynes and symmetrical diynes. Cross-coupling reactions of hydrazones with halides and terminal alkynes were performed to afford functionalized alkynes and unsymmetrical conjugated diynes. A mechanism proceeding through a Cu-carbene intermediate is proposed for the CC triple bond formation.