Yongqin He

PhI(OAc)2 oxidative C5 halogenation of quinolines using copper halides under mild conditions

A concise and efficient protocol for PhI(OAc)2 oxidation halogenation of quinoline at the C5 position was developed, affording the desired remote C–H activation products in moderate to excellent yields. This reaction proceeds with copper halides as the halogenating reagent to afford the halogenated quinolines and features excellent substrate tolerance, providing a facile pathway for the C5 halogenation of quinoline.

Copper-Mediated Aerobic Oxidative Synthesis of 3-Bromo-imidazo[1,2-a]pyridines with Pyridines and Enamides

A conversion of pyridines and enamides for the synthesis of 3-bromo-imidazo[1,2-a]pyridines was developed by copper-mediated aerobic oxidative coupling in a one-pot manner. This procedure tolerates various functional groups and affords a series of 3-bromo-imidazo[1,2-a]pyridines under mild conditions.

Metal free synthesis of 2,4-diarylquinoline derivatives with enamides and imines

A metal free I2-catalyzed cyclization between enamides and imines has been developed. This approach is available for a broad range of substrates and provides an extremely simple and efficient way to construct heteroaromatic quinoline derivatives.

Oxidative Recyclization of 1H-Indoles for Synthesis of 2-Indolylbenzoxazinones via Cleavage of the C2–C3 Bond with AIBN under Air

A novel and concise method for the oxidation of unprotected indole derivatives to synthesize 2-indolylbenzoxazinones in the presence of AIBN under open air has been successfully demonstrated. This metal-free reaction is both atom- and step-efficient and is applicable to a broad scope of substrates. This new methodology provides a facile pathway for oxidative C2-C3 bond cleavage and recyclization of 1H-indoles.

Iodine-Mediated Domino Oxidative Cyclization: One-Pot Synthesis of 1,3,4-Oxadiazoles via Oxidative Cleavage of C(sp2)–H or C(sp)–H Bond

An I2-promoted, metal-free domino protocol for one-pot synthesis of 1,3,4-oxadiazoles has been developed via oxidative cleavage of C(sp(2))-H or C(sp)-H bonds, followed by cyclization and deacylation. In this reaction, the use of K2CO3 as a base is found to be an essential factor in the cyclization and the C-C bond cleavage. This procedure proceeded smoothly in moderate to high yields with good functional group compatibility.

Pd-Catalyzed Ligand-Free Synthesis of Arylated Heteroaromatics by Coupling of N-Heteroaromatic Bromides with Iodobenzene Diacetate, Iodosobenzene, or Diphenyliodonium Salts

An efficient method for synthesizing arylated heteroaromatics has been reported via Pd-catalyzed ligand-free cross-coupling of N-heteroaromatic bromides with iodine(III) reagents under mild conditions. Iodobenzene diacetate, iodosobenzene, and diphenyliodonium salts act as ideal arylated sources in this reaction, producing bioactive aromatic-substituted pyridines and quinolines in moderate to high yields.