Fengxiang Zhu

Iron‐Catalyzed Hydrogenation of Bicarbonates and Carbon Dioxide to Formates

The catalytic hydrogenation of carbon dioxide and bicarbonate to formate has been explored extensively. The vast majority of the known active catalyst systems are based on precious metals. Herein, we describe an effective, phosphine-free, air- and moisture-tolerant catalyst system based on Knölkers iron complex for the hydrogenation of bicarbonate and carbon dioxide to formate. The catalyst system can hydrogenate bicarbonate at remarkably low hydrogen pressures (1-5 bar).

Copper‐Catalyzed Carbonylative Coupling of Cycloalkanes and Amides

Carbonylation reactions are a most powerful method for the synthesis of carbonyl-containing compounds. However, most known carbonylation procedures still require noble-metal catalysts and the use of activated compounds and good nucleophiles as substrates. Herein, we developed a copper-catalyzed carbonylative transformation of cycloalkanes and amides. Imides were prepared in good yields by carbonylation of a C(sp(3) )-H bond of the cycloalkane with the amides acting as weak nucleophiles. Notably, this is the first report of copper-catalyzed carbonylative C-H activation.

Iridium-Catalyzed and Ligand Controlled Carbonylative Synthesis of Flavones from Simple Phenols and Internal Alkynes

Flavones are important natural products with diverse biological activities. In this study, a novel procedure for the carbonylative synthesis of flavones has been developed by using simple phenols and internal alkynes as the substrates. Various flavones were isolated in moderate to good yields with excellent regioselectivity and functional group tolerance by using an iridium catalyst system. Notably, this is the first example of direct carbonylative annulation of non-preactivated phenols and alkynes to produce flavones, with the choice of ligand proving to be critical for the success of this transformation.

Iridium-Catalyzed Carbonylative Synthesis of Chromenones from Simple Phenols and Internal Alkynes at Atmospheric Pressure

A novel procedure on the carbonylative synthesis of chromenones has been developed. With simple phenols and internal alkynes as the substrates, various chromenones were isolated in moderate to good yields with excellent regioselectivity and functional-group tolerance by using iridium as the catalyst and copper as the promotor at atmospheric pressure. Notably, this is the first example on carbonylative annulation of simple phenols and alkynes.

Palladium-Catalyzed Construction of Amidines from Arylboronic Acids under Oxidative Conditions.

A valuable palladium-catalyzed three-component coupling reaction for the synthesis of amidines has been developed. Using arylboronic acids, isocyanides, and anilines as the reactants under oxidative conditions, various amidines were isolated in good yields with good functional group tolerances.

Highly efficient synthesis of flavones via Pd/C-catalyzed cyclocarbonylation of 2-iodophenol with terminal acetylenes

A highly efficient and selective Pd/C-catalyzed ligand-free cyclocarbonylation reaction for the synthesis of flavones has been developed. Various flavone derivatives were isolated in excellent yields with excellent functional group tolerances. Additionally, catalyst reuse experiments were performed successfully as well.

An unexpected copper-catalyzed carbonylative acetylation of amines

A novel copper-catalyzed carbonylative acetylation of amines has been developed. With peroxide as the oxidant as well as the methyl source with a copper catalyst under CO pressure, good yields of N-acetyl amides could be obtained. Notably, this is the first example of carbonylative acetylation.

Practical and General Manganese-Catalyzed Carbonylative Coupling of Alkyl Iodides with Amides

A selective manganese‐catalyzed carbonylative transformation of alkyl iodides and amides was developed. A variety of imides were prepared in moderate to good yields. Alkyl bromides could also be applied by in situ treatment with NaI to give the corresponding alkyl iodides. Notably, no additives or expensive ligands were required here. As the first example of the carbonylative coupling of alkyl iodides with amides, the simple reaction conditions and the advantages of a manganese catalyst make this new general procedure more attractive and practical than conventional techniques. Mechanistically, control experiments and electron paramagnetic resonance spectroscopy studies were also performed, and the radical nature of this new process was proven.

Copper‐Catalyzed Alkoxycarbonylation of Alkanes with Alcohols

Esters are important chemicals widely used in various areas, and alkoxycarbonylation represents one of the most powerful tools for their synthesis. In this communication, a new copper-catalyzed carbonylative procedure for the synthesis of aliphatic esters from cycloalkanes and alcohols was developed. Through direct activation of the Csp3 -H bond of alkanes and with alcohols as the nucleophiles, the desired esters were prepared in moderate-to-good yields. Paraformaldehyde could also be applied for in situ alcohol generation by radical trapping, and moderate yields of the corresponding esters could be produced. Notably, this is the first report on copper-catalyzed alkoxycarbonylation of alkanes.

Palladium‐Catalyzed Carbonylative Synthesis of 3‐Methyleneisoindolin‐1‐ones from Ketimines with Mo(CO)6 as the CO Source

An interesting procedure for the palladium‐catalyzed carbonylative synthesis of 3‐methyleneisoindolin‐1‐ones from ketimines was established. By using Mo(CO)6 (0.3 equiv.) as the solid CO source and through C(sp2)−H bond activation, the desired 3‐methyleneisoindolin‐1‐ones were isolated in moderate to good yields.