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This article discusses the challenges and importance of selectively functionalizing C-H bonds in organic molecules, particularly C(sp3)-H bonds. The authors focus on the azolation of benzylic C-H bonds under photoredox catalysis and aim to understand the reaction mechanism and regioselectivity. Through a computational study using density functional theory, they investigate the full photoredox catalytic cycle and characterize the steps involved in the reaction. The study provides insights into the origins of regioselectivity and contributes to the understanding of C-H azolation within photoredox systems. [Extracted from the article]

Dioxazolones, which are potent amide precursors, have been widely explored for the formation of C–N bonds with the help of transition-metal catalysts. Here, we highlight our recent studies on the synthesis of N -aryl amides using dioxazolones and boronic acids in the presence of copper(I) chloride under mild conditions. The versatility of the developed reaction is demonstrated by its wide range of functional-group tolerances as well as the release of nontoxic carbon dioxide. Optimization screenings reveal that a fluorine additive improves the desired reactivity toward the intended transformation. The addition of triphenylphosphine results in an N -acyl iminophosphorane, suggesting the involvement of an N -acyl nitrene intermediate in this transformation. [ABSTRACT FROM AUTHOR]

Straightforward synthesis of quinazolinones having N-fused medium-sized ring urea was accomplished. Key intermediates were tert -butyl {2-[4-oxo-2-(4-oxopentyl)quinazolin-3(4 H)-yl]ethyl}carbamates derived from copper-catalyzed domino reaction of tert -butyl [2-(2-iodobenzamido)ethyl]carbamates and cyclic enaminones. Steric hindrance of cyclic enaminones played an important role in the formation of quinazolinone ring. The eleven-membered ring urea moiety was readily achieved by direct cyclization using 1,1′-carbonyldiimidazole (CDI) of diamino intermediate generated by readily reductive amination and deprotection of tert -butyl {2-[4-oxo-2-(4-oxopentyl)quinazolin-3(4 H)-yl]ethyl}carbamates. [ABSTRACT FROM AUTHOR]

A one-pot direct synthesis of xanthine and uric acid derivates is reported. This simple yet efficient methodology illustrates concurrent formation of two C–N bonds using CuBr2 as catalyst and one of those C–N bonds is formed by uracil C6–H bond activation. [ABSTRACT FROM AUTHOR]

For years, metal–nitrene-transfer reactions have been mainly directed toward C=C bond aziridination or C–H bond amidation reactions. In the last decade, multiple efforts have been made to develop new synthetic approaches to expand the applicability of this powerful tool, resulting in the synthesis of complex structures from relatively simple starting materials. Here, we present our contributions to the area with several novel and, to some degree, unexpected transformations developed by our research group. The catalysts for these nitrene-transfer reactions are copper or silver complexes bearing hydrotrispyrazolyl (scorpionate) ligands. These transformations have contributed to an expansion of the scope of organic compounds accessible by nitrene-transfer reactions and to an understanding of the reactivity of metallonitrene species toward the oxidation of less-explored organic substrates. 1 Introduction 2 Synthesis of 1,2-Dihydropyridines from Furans 3 Regio- and Stereoselective Aziridination of Dienes 4 Chemoselective Synthesis of Aminimides from Amines 5 Synthesis of Sulfinamides and Isothiazoles from Alkynes 6 Formation of Azetidines and Methylene Aziridines from Allenes 7 Conclusion [ABSTRACT FROM AUTHOR]

Engineered myoglobins have recently gained attention for their ability to catalyze a variety of abiological carbene transfer reactions including the functionalization of amines via carbene insertion into N–H bonds. However, the scope of myoglobin and other hemoprotein-based biocatalysts in the context of this transformation has been largely limited to aniline derivatives as the amine substrates and ethyl diazoacetate as the carbene donor reagent. In this report, we describe the development of an engineered myoglobin-based catalyst that is useful for promoting carbene N–H insertion reactions across a broad range of substituted benzylamines and α-diazo acetates with high efficiency (82–99% conversion), elevated catalytic turnovers (up to 7,000), and excellent chemoselectivity for the desired single insertion product (up to 99%). The scope of this transformation could be extended to cyclic aliphatic amines. These studies expand the biocatalytic toolbox available for the selective formation of C–N bonds, which are ubiquitous in many natural and synthetic bioactive compounds. [ABSTRACT FROM AUTHOR]

An efficient and convenient Ni-catalyzed C-N bond formation for the synthesis of various benzimidazoles from various 2-haloanilines, aldehydes, and ammonia in a concise manner is reported. This protocol uses commercially available, nonhazardous, clean ammonia as a reaction partner instead of other nitrogen sources. Benzimidazoles, as the sole products, were obtained in high to excellent yields (up to 95%). [ABSTRACT FROM AUTHOR]

An efficient one-pot synthesis of quinazolino[4,3-b]quinazoline derivatives has been accomplished, starting from 2-(2-bromophenyl) quinazolin-4(3H)-one, aldehydes, and various nitrogen sources under aerobic conditions. The multicomponent protocol is mediated by copper(I) salts and involves amination of 2-(2-bromophenyl)quinazolin-4(3H)-one, followed by condensation with the aldehyde and an oxidative cyclization to give the target compounds in moderate to good yields. [ABSTRACT FROM AUTHOR]

An efficient synthesis of benzhydrazides has been achieved through the direct acylation of azodicarboxylates with benzylic alcohols in moderate to high yields. The method represents the first practical approach to amides containing a hydrazine structural unit from benzylic alcohols. [ABSTRACT FROM AUTHOR]

Nickel-catalyzed N-arylation reaction of N-trimethylsilyl-carbazole using aryl bromides is found to proceed in the presence of sodium acetate, giving N-aryl-carbazoles in high yields. Under these conditions, N-trimethylsilyl-carbazole could react with aryl bromides selectively even in the presence of other N-trimethylsilyl-amines or NH- amines. This arylation reaction was applied to the polymerization to provide a polycarbazole. [ABSTRACT FROM AUTHOR]

A radical-radical cross-coupling reaction of phenols with tert-butyl nitrite has been developed with the use of water as an additive. This method allows the construction of C-N bonds under an air atmosphere at room temperature, providing the ortho-nitrated phenol derivative in moderate to good yields. [ABSTRACT FROM AUTHOR]

An efficient approach to the synthesis of benzimidazole derivatives has been achieved by copper-catalyzed double C–N bonds formation of N-alkyl-2-iodoaniline and sodium azide. The reaction was supposed to proceed through copper-catalyzed tandem reaction of SNAr reaction, aerobic oxidation of C(sp3)–H bond and intramolecular C–N bond formation sequence. Structurally diverse 2-aryl, alkenyl and alkyl benzoimidazole derivatives were assembled by this methodology. [ABSTRACT FROM AUTHOR]

A direct approach to access important α-amino phosphonic acids and their derivatives through the formation of C–N bonds is described. Several α-amination reactions of phosphonates that involve electrophilic aminating agents are reviewed. A recent development is highlighted in which an acyclic or cyclic amine is introduced into the α-position of a phosphonate in one step through deprotonative formation of an α-zincate followed by copper-catalyzed amination with an O-acylhydroxylamine. [ABSTRACT FROM AUTHOR]