Catalytic dehydrogenative cross-coupling: forming carbon-carbon bonds by oxidizing two carbon-hydrogen bonds

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Aryl-aryl bond formation one century after the discovery of the Ullmann reaction.

The direct functionalization of C-H bonds in organic compounds has recently emerged as a powerful and ideal method for the formation of carbon-carbon and carbon-heteroatom bonds. This Review provides an overview of C-H bond functionalization strategies for the rapid synthesis of biologically active compounds such as natural products and pharmaceutical targets.

C-H bond functionalization: emerging synthetic tools for natural products and pharmaceuticals

This Review covers recent progress on near-infrared fluorescence imaging for preclinical animal studies and clinical diagnostics and interventions.

Near-infrared fluorophores for biomedical imaging

Since the discovery of organic azides by Peter Griess more than 140 years ago, numerous syntheses of these energy-rich molecules have been developed. In more recent times in particular, completely new perspectives have been developed for their use in peptide chemistry, combinatorial chemistry, and heterocyclic synthesis. Organic azides have assumed an important position at the interface between chemistry, biology, medicine, and materials science. In this Review, the fundamental characteristics of azide chemistry and current developments are presented. The focus will be placed on cycloadditions (Huisgen reaction), aza ylide chemistry, and the synthesis of heterocycles. Further reactions such as the aza-Wittig reaction, the Sundberg rearrangement, the Staudinger ligation, the Boyer and Boyer-Aube rearrangements, the Curtius rearrangement, the Schmidt rearrangement, and the Hemetsberger rearrangement bear witness to the versatility of modern azide chemistry.

Organic Azides: An Exploding Diversity of a Unique Class of Compounds

Quinolinetrione-tacrine hybrids as multi-target-directed ligands against Alzheimer's disease

The microwave-assisted reaction of 2-nitroimidazole with 3-bromophenacyl bromide in the presence of potassium carbonate as a base and dimethylformamide as a solvent afforded 2-(3-bromophenyl)imidazo[2,1-b]oxazole. The formation of this compound was explained via a domino mechanism comprising an initial N-alkylation reaction of the imidazole substrate, followed by the base-promoted deprotonation of the position adjacent to the carbonyl to give an enolate anion that finally cyclizes via an intramolecular SNAr reaction, with the loss of the nitro group as potassium nitrite. Then, the proposed 1-(3-bromophenacyl)-2-nitroimidazole intermediate could be isolated by reducing the reaction time and was shown to be a precursor of the imidazo[2,1-b]oxazole final product.

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2-(3-Bromophenyl)imidazo[2,1-b]oxazole

The reaction of vinyl Grignard reagents with o-methoxynitroarenes containing an electron-releasing substituent para to the nitro group proceeds through a pathway that is different from the initially expected Bartoli indole synthesis. Thus, instead of giving fused indole derivatives, these reactions provide a very mild and efficient new procedure for the synthesis of synthetically relevant aromatic systems containing an o-nitrovinyl moiety, such as 5-nitro-4-vinylindoles, 6-nitro-7-vinylindoles, 6-nitro-5-vinyl-2(1H)quinolinones, and 4-nitro-3-vinyl-anilines.

Vinylation of Nitro‐Substituted Indoles, Quinolinones, and Anilides with Grignard Reagents.

DBU-promoted alkylation of cyclic α-nitroketones (I) with o-bromobenzyl halides, e.g. (II), (V) or (VIII), followed by Pd-catalyzed intramolecular C-arylation provides an efficient access towards benzo-fused bicyclo[n.3.1]alkane derivatives (III), (VI) and (IX), respectively.

Synthesis of Benzo‐ and Naphtho‐Fused Bicyclo[n.3.1]alkane Frameworks with a Bridgehead Nitrogen Function by Palladium‐Catalyzed Intramolecular α′‐Arylation of α‐Nitroketones.

Cerium(IV) Ammonium Nitrate Is an Excellent, General Catalyst for the Friedlaender and Friedlaender—Borsche Quinoline Syntheses: Very Efficient Access to the Antitumor Alkaloid Luotonin A.

J. Carlos Menéndez

Papers

Quinolinetrione-tacrine hybrids as multi-target-directed ligands against Alzheimer's disease

2-(3-Bromophenyl)imidazo[2,1-b]oxazole

Vinylation of Nitro‐Substituted Indoles, Quinolinones, and Anilides with Grignard Reagents.

Synthesis of Benzo‐ and Naphtho‐Fused Bicyclo[n.3.1]alkane Frameworks with a Bridgehead Nitrogen Function by Palladium‐Catalyzed Intramolecular α′‐Arylation of α‐Nitroketones.

Cerium(IV) Ammonium Nitrate Is an Excellent, General Catalyst for the Friedlaender and Friedlaender—Borsche Quinoline Syntheses: Very Efficient Access to the Antitumor Alkaloid Luotonin A.