Transition-Metal-Catalyzed C−S, C−Se, and C−Te Bond Formation via Cross-Coupling and Atom-Economic Addition Reactions

This critical review examines transition metal-catalyzed decarboxylative couplings that have emerged within recent years as a powerful strategy to form carbon–carbon or carbon–heteroatom bonds starting from carboxylic acids. In these reactions, C–C bonds to carboxylate groups are cleaved, and in their place, new carbon–carbon bonds are formed. Decarboxylative cross-couplings constitute advantageous alternatives to traditional cross-coupling or addition reactions involving preformed organometallic reagents. Decarboxylative reaction variants are also known for Heck reactions, direct arylation processes, and carbon–heteroatom bond forming reactions.

Decarboxylative coupling reactions: a modern strategy for C–C-bond formation

Cu-catalysed arylation reactions devoted to the formation of C–C and C–heteroatom bonds (Ullmann-type couplings) have acquired great importance in the last decade. This review discusses the history and development of coupling reactions between aryl halides and various classes of nucleophiles, focusing mostly on the different mechanisms proposed through the years. Selected mechanistic investigations are treated more in depth than others. For example, evidence in favour or against radical mechanisms is discussed. Cu(I) and Cu(III) complexes involved in the Ullmann reaction and N/O selectivity in aminoalcohol arylation are discussed. A separate section has been dedicated to the synthesis of heterocyclic rings through intramolecular couplings. Finally, recent developments in green chemistry for these reactions, such as reactions in aqueous media and heterogeneous catalysis, have also been reviewed.

https://pubs.rsc.org/en/content/getauthorversionpdf/C3CS60289C

Copper catalysed Ullmann type chemistry: From mechanistic aspects to modern development

Transition metal-catalyzed decarboxylative cross-coupling reactions have recently emerged as a new and important category of organic transformations that find versatile applications in the construction of carbon-carbon and carbon-heteroatom bonds. The use of relatively cheap and stable carboxylic acids to replace organometallic reagents enables the decarboxylative cross-coupling reactions to proceed with good selectivities and functional group tolerance. In the present review we summarize the various types of decarboxylative cross-coupling reactions catalyzed by different transition metal complexes. The scope and applications of these reactions are described. The challenges and opportunities in the field are discussed.

Transition metal-catalyzed decarboxylative cross-coupling reactions

The synthesis of substituted benzimidazoles, 2-aminobenzimidazoles, 2-aminobenzothiazoles, and benzoxazoles is described via intramolecular cyclization of o-bromoaryl derivatives using copper(II) oxide nanoparticles in DMSO under air. The procedure is experimentally simple, general, efficient, and free from addition of external chelating ligands. It is a heterogeneous process and the copper(II) oxide nanoparticles can be recovered and recycled without loss of activity.

Ligand-Free Copper-Catalyzed Synthesis of Substituted Benzimidazoles, 2-Aminobenzimidazoles, 2-Aminobenzothiazoles, and Benzoxazoles

Copper(I)-catalyzed tandem reaction of 2-iodobenzenamine with isothiocyanate under mild conditions is described, which provides an efficient and practical route for the synthesis of 2-aminobenzothiazole.

Synthesis of 2-aminobenzothiazole via copper(I)-catalyzed tandem reaction of 2-iodobenzenamine with isothiocyanate.

A highly effective decarboxylative cross-coupling reaction of cinnamic acid with aryl iodide catalyzed by the combination of palladium chloride and CyJohnPhos in the presence of Ag2CO3 as an additive is described. The desired carbon-carbon bond formation proceeds efficiently with good functional-group tolerance.

Xiaodan He

Papers

Synthesis of 2-aminobenzothiazole via copper(I)-catalyzed tandem reaction of 2-iodobenzenamine with isothiocyanate.

Palladium-catalyzed decarboxylative cross-coupling reaction of cinnamic acid with aryl iodide

Multicatalytic synthesis of 1,2-dihydroisoquinolin-1-ylphosphonates via a tandem four-component reaction

Pd-catalyzed decarboxylative couplings of arenecarboxylic acids with aryl iodides

Palladium-Catalyzed Decarboxylative Cross-Coupling Reaction of Cinnamic Acid with Aryl Iodide.