Over the past several decades, organometallic cross-coupling chemistry has developed into one of the most reliable approaches to assemble complex aromatic compounds from preoxidized starting materials. More recently, transition metal–catalyzed carbon-hydrogen activation has circumvented the need for preoxidized starting materials, but this approach is limited by a lack of practical amination protocols. Here, we present a blueprint for aromatic carbon-hydrogen functionalization via photoredox catalysis and describe the utility of this strategy for arene amination. An organic photoredox-based catalyst system, consisting of an acridinium photooxidant and a nitroxyl radical, promotes site-selective amination of a variety of simple and complex aromatics with heteroaromatic azoles of interest in pharmaceutical research. We also describe the atom-economical use of ammonia to form anilines, without the need for prefunctionalization of the aromatic component.

Site-selective arene C-H amination via photoredox catalysis

Synthesis of indazole motifs and their medicinal importance: an overview.

Organoindium reagents: the preparation and application in organic synthesis.

Zinc is the 24th most abundant element in the Earth’s crust. Since the discovery of pure zinc metal in the 18th century, the main application of zinc metal is as materials. Because zinc salts are abundant, cheap, non-toxic, and exhibit environmentally benign properties, organic chemists have been interested in using zinc salts as catalysts in organic synthesis during the last three decades. Within this review, we have summarized the progress on applications of zinc salts in organic reactions. Our the target is to emphasize the special properties of zinc catalysts, and further promote the interest of organic chemists.

Zinc-Catalyzed Organic Synthesis: CC, CN, CO Bond Formation Reactions

Ruthenium Catalyzed Reductive Coupling of Paraformaldehyde to Trifluoromethyl Allenes: CF3-Bearing All-Carbon Quaternary Centers

A method for the regioselective synthesis of 1-alkyl-1H-indazoles

Simple and mild methods for the synthesis of allenes, employing indium- and zinc-mediated dehalogenation reactions of vicinal dihalides in an aqueous solvent, are described. By using these procedures, various allenylmethyl aryl ethers and monosubstituted allenes have been prepared in good to excellent yields.

Methods for the Preparation of Allenes Employing Indium- and Zinc-Mediated Dehalogenation Reactions in Aqueous Solutions

Methods for the Preparation of Allenes Employing Indium- and Zinc-Mediated Dehalogenation Reactions in Aqueous Solutions.

A method for the regioselective synthesis of 3-unsubstituted 1-alkyl-1H-indazoles, starting with 2-halobenzonitriles and N-alkylhydrazines, is described. The two-step reaction pathway proceeds through the intermediacy of 1-alkyl-3-amino-1H-indazoles followed by reductive deamination.

Shiang Fu Hung

Papers

A method for the regioselective synthesis of 1-alkyl-1H-indazoles

Methods for the Preparation of Allenes Employing Indium- and Zinc-Mediated Dehalogenation Reactions in Aqueous Solutions

Methods for the Preparation of Allenes Employing Indium- and Zinc-Mediated Dehalogenation Reactions in Aqueous Solutions.

A Method for the Regioselective Synthesis of 1-Alkyl-1H-indazoles.