Jianyu Dong

Metal- and Oxidant-Free Synthesis of Quinazolinones from β-Ketoesters with o-Aminobenzamides via Phosphorous Acid-Catalyzed Cyclocondensation and Selective C–C Bond Cleavage

A general and efficient phosphorous acid-catalyzed cyclocondensation of β-ketoesters with o-aminobenzamides via selective C-C bond cleavage leading to quinazolinones is developed. This reaction proceeds smoothly under metal- and oxidant-free conditions, giving both 2-alkyl- and 2-aryl-substituted quinazolinones in excellent yields. This strategy can also be applied to the synthesis of other N-heterocycles, such as benzimidazoles and benzothiazoles.

Copper Catalysis for Selective Heterocoupling of Terminal Alkynes

A Cu-catalyzed selective aerobic heterocoupling of terminal alkynes is disclosed, which enables the synthesis of a broad range of unsymmetrical 1,3-diynes in good to excellent yields. The results disprove the long-held belief that homocouplings are exclusively favored in the Glaser-Hay reaction.

Metal-Free Oxidative Annulation of 2-Naphthols with Terminal Alkynes Affording 2-Arylnaphtho[2,1-b]furans

For the first time, the selective oxidative transformation of 2-naphthols with terminal alkynes is disclosed, which enables the straightforward synthesis of 2-arylnaphtho[2,1-b]furans in satisfactory yields under metal-free conditions. Mechanistic study suggests that the reaction proceeds via free-radical-mediated sp(2)-C-H bond activation, C-C coupling, and C-O cyclization.

Palladium-Catalyzed Desulfitative Cross-Coupling of Arylsulfonyl Hydrazides with Terminal Alkynes: A General Approach toward Functionalized Internal Alkynes

A palladium-catalyzed Sonogashira-type coupling between arylsulfonyl hydrazides and terminal alkynes via Ar(C)-S bond cleavage is disclosed, which enables the general synthesis of functionalized internal alkynes, especially the Br-substituted ones, in good to excellent yields under acid- and base-free conditions.

Selective Aerobic C–H Amination of Phenols with Primary Amines over Copper toward Benzoxazoles

Using O2 as the oxidant, the benzoxazole frameworks can be directly constructed from the readily available phenols and primary amines in the presence of NH4PF6 over copper under mild conditions. Mechanistic studies showed that a novel mechanism involving biphenyldiols and o-quinones very possibly takes effect in the reaction, because both can selectively give the benzoxazoles under the reaction conditions. An unprecedented unstrained Caryl-Caryl bond cleavage takes place in the reaction.

Palladium-Catalyzed Regio- and Stereoselective Coupling–Addition of Propiolates with Arylsulfonyl Hydrazides: A Pattern for Difunctionalization of Alkynes

A new pattern for difunctionalization of alkynes via a palladium-catalyzed regio- and stereoselective coupling-addition of propiolates with arylsulfonyl hydrazides is disclosed. The approach enables the synthesis of various highly functionalized ( E)-vinylsulfones in satisfactory yields. Arylsulfonyl hydrazides act as both aryl and sulfonyl sources via selective cleavage of Ar(C)-S and S-N bonds, which are simultaneously incorporated onto the terminal carbon atom of an alkyne molecule.

Cyclization of Ketones with Nitriles under Base: A General and Economical Synthesis of Pyrimidines

A facile, general, and economical synthesis of diversely functionalized pyrimidines has been realized under basic conditions via the copper-catalyzed cyclization of ketones with nitriles. The reaction proceeds via a novel pathway involving the nitriles acting as electrophiles and consecutive C-C bond and two C-N bond formations and shows broad substrate scope and good tolerance of many important functional groups. This strategy represents a new platform for constructing pyrimidine structures.

Transition-Metal-Free C–P Bond Formation via Decarboxylative Phosphorylation of Cinnamic Acids with P(O)H Compounds

A novel, transition-metal-free phosphorylation of cinnamic acids with P(O)H compounds has been developed via radical-promoted decarboxylation under mild conditions. This method provides simple, efficient, and versatile access to valuable ( E)-alkenylphosphine oxides in satisfactory yields with a wide variety of substrates.

Cu-mediated nitrogen atom transfer via C equivalent to N bond cleavage

A nitrogen atom transfer to organic molecules via Cu-mediated C-N triple bond cleavage is firstly developed, which provides a variety of functionalized aryl nitriles from the readily accessible acetonitrile and aryl aldehydes.