Palladium-catalyzed amination reactions of aryl halides have undergone rapid development in the last 12 years, largely driven by the implementation of new classes of ligands. Biaryl phosphanes have proven to provide especially active catalysts in this context. This Review discusses the application of these catalysts in C-N cross-coupling reactions in the synthesis of heterocycles and pharmaceuticals, in materials science, and in natural product synthesis.

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Biaryl Phosphane Ligands in Palladium‐Catalyzed Amination

Pd-catalyzed cross-coupling reactions that form C–N bonds have become useful methods to synthesize anilines and aniline derivatives, an important class of compounds throughout chemical research. A key factor in the widespread adoption of these methods has been the continued development of reliable and versatile catalysts that function under operationally simple, user-friendly conditions. This review provides an overview of Pd-catalyzed N-arylation reactions found in both basic and applied chemical research from 2008 to the present. Selected examples of C–N cross-coupling reactions between nine classes of nitrogen-based coupling partners and (pseudo)aryl halides are described for the synthesis of heterocycles, medicinally relevant compounds, natural products, organic materials, and catalysts.

Applications of Palladium-Catalyzed C–N Cross-Coupling Reactions

Dialkylbiaryl phosphines are a valuable class of ligand for Pd-catalyzed amination reactions and have been applied in a range of contexts. This perspective attempts to aid the reader in the selection of the best choice of reaction conditions and ligand of this class for the most commonly encountered and practically important substrate combinations.

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Dialkylbiaryl Phosphines in Pd-Catalyzed Amination: A User's Guide.

Dialkylbiaryl phosphines in Pd-catalyzed amination: a user's guide

DNA Cross-Linking Agents as Antitumor Drugs.

Prodrug approach: An overview of recent cases.

Synthesis of carbo- and heterobiaryls by intermolecular radical addition of aryl bromides onto aromatic solvents

New azaquinolizinium-type cations have been obtained from isochromane. The synthesis was completed over seven steps and included as the key feature an intramolecular Westphal condensation. This first example of the intramolecular process allowed the preparation of benzo-[f]pyrido[2,1-a]phthalazinium and benzo[f]quino[2,1-a]phthalazinium salts, which were evaluated as DNA intercalators, DNA topoisomerase I inhibitors, and antiproliferative compounds. Both cationic systems behave as DNA intercalators and exhibit antiproliferative activity. The pentacyclic benzo[f]quino[2,1-a]phthalazinium cations also have an inhibitory effect on the catalytic activity of DNA topoisomerase I, without trapping of cleavage complexes. Structural characterization using density functional theory indicates that the fused ring systems are slightly nonplanar, and additional molecular modeling studies suggest a preferred orientation for the intercalating chromophores within a typical CpG or TpG intercalation site.

http://www3.uah.es/farmamol/Public/PDF_files_FGago/JMC2004_intercal.pdf

Benzo[f]azino[2,1-a]phthalazinium cations: novel DNA intercalating chromophores with antiproliferative activity.

Synthesis of biaryls via intermolecular radical addition of heteroaryl and aryl bromides onto arenes

The synthesis of dipyridopyrazole and pyridopyrazolopyrazine derivatives—both of which incorporate a 3-aryl moiety—can be achieved in moderate yields by intramolecular radical arylation of pyridinium N-aminides using tris(trimethylsilyl)silane and azobisisobutyronitrile. Improved results were obtained on using Pd direct arylation in conjunction with microwave irradiation. A preliminary study into the fluorescent properties of the target compounds is also reported.

A new class of pyrazolopyridine nucleus with fluorescent properties, obtained through either a radical or a Pd arylation pathway from N-azinylpyridinium N-aminides.

Carolina Burgos

Papers

Prodrug approach: An overview of recent cases.

Synthesis of carbo- and heterobiaryls by intermolecular radical addition of aryl bromides onto aromatic solvents

Benzo[f]azino[2,1-a]phthalazinium cations: novel DNA intercalating chromophores with antiproliferative activity.

Synthesis of biaryls via intermolecular radical addition of heteroaryl and aryl bromides onto arenes

A new class of pyrazolopyridine nucleus with fluorescent properties, obtained through either a radical or a Pd arylation pathway from N-azinylpyridinium N-aminides.