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A new approach for the preparation of a variety of 3-arylated 2-furoic acid derivatives has been developed. The approach involves selective Ru-catalyzed C3-H arylation of the furan moiety of readily available 2-furoyl-1-methylimidazole (using imidazole as a removable N-donor directing group), subsequent N-methylation, and nucleophilic substitution of the imidazole moiety with N, O, S, and C nucleophiles. [ABSTRACT FROM AUTHOR]

Fluorinated molecules are widely used in pharmaceutical and agrochemical industries. Multifluoroalkyl-containing compounds have attracted increasing attention for their unique ability to alter the activity of drugs and bioactive molecules. Herein, we report an efficient Rh(III)-catalyzed, redox-neutral, C–H multifluoroalkenylation of benzamides with multifluoroalkenes, which provides a versatile protocol for accessing a wide range of multifluoroalkenylated arenes. [ABSTRACT FROM AUTHOR]

Reported here is the iridium-catalyzed regio- and enantio-selective secondary benzylic C–H borylation using benzothiazole as the directing group. Various monosubstituted 2-arylalkylbenzo[ d ]thiazole were well-tolerated, affording the corresponding products in moderate to good yields with good enantioselectivity. The C–B bond in one boryl-ated product could undergo stereospecific transformations to form a series of C–C and C–heteroatom bonds. [ABSTRACT FROM AUTHOR]

This short review showcases the developing field of C–H activation reactions, with a particular focus on green catalysis through the use of environmentally friendly solvents. It evaluates the effects of these solvents on reaction outcomes, environmental aspects and general efficacy, highlighting their advantages that lead to greater selectivity, lower levels of toxicity and enhanced reaction rates. Water and biobased alternatives such as polyethylene glycols, glycerol, 2-methyltetrahydrofuran, γ-valerolactone, methanol, ethanol, p -cymene and diethyl carbonate are representative examples of such solvents. The scope of this short review encompasses studies of different methodologies, catalysts, and reaction conditions that help to develop C–H activation reactions utilizing green solvents. 1 Introduction 2 Water 3 Polyethylene Glycols (PEGs) 4 Glycerol 5 2-Methyltetrahydrofuran (2-MeTHF) 6 γ-Valerolactone (GVL) 7 Methanol 8 Ethanol 9 p -Cymene 10 Diethyl Carbonate 11 Conclusion [ABSTRACT FROM AUTHOR]

This article discusses a new method for synthesizing homoallylic alcohols, which are commonly found in synthetic intermediates and bioactive molecules. The authors describe a three-component reaction using specific catalysts, which allows for the creation of a diverse range of homoallylic alcohols. The article also includes detailed procedures for the synthesis and purification of these compounds, as well as their characterization using various analytical techniques. The information is presented in a technical manner and is intended for researchers in the field. [Extracted from the article]

This article provides a comprehensive report on the rhodium(III)-catalyzed C–H activation in indole from 2017 to 2022. The direct functionalization of C–H bonds offers a more sustainable and economically sensible route in organic synthesis, reducing the production of hazardous waste. Rhodium has been widely used as a catalyst for C–H functionalization due to its excellent functional group compatibility, versatility, reactivity, and selectivity. The article focuses on the utilization of Rh(III) catalyst for C–H activation of the indole moiety, which is a structurally important building block in natural products and pharmaceutical treatments. Various methods for directed C–H functionalization of indoles, such as C2 activation, alkylation, hydroarylation, and dual C–H activation reactions, are discussed. The text also discusses various methods for the synthesis of carbazole derivatives, benzo[e]indoles, and selective functionalization of indoles through C–H activation. While progress has been made in this area, there are still challenges to overcome, such as the need for harsh reaction conditions and stoichiometric metal oxidants. Continued research in this field is expected to improve reaction conditions and increase overall efficiency. [Extracted from the article]

This article explores the use of pyrazolopyridine ligands in transition-metal-catalyzed reactions. These ligands have a wide range of effects and have been used in various oxidative and reductive reactions, as well as in applications such as solar cells and organic light-emitting diodes. The article discusses the synthesis of these ligands and their role in facilitating the formation of C-C and C-heteroatom bonds. It also provides specific examples of their use in different catalytic reactions, highlighting the importance of ligand design. The article encourages further research into the potential of pyrazolopyridine ligands in catalytic processes. [Extracted from the article]

This article provides a comprehensive overview of the synthesis and modification of organic fluorophores, which are organic compounds that emit light when excited. It discusses various synthetic reactions used to create these fluorescent molecules, with a focus on transition-metal-catalyzed C–H activation reactions. The article categorizes recent C–H activation reactions and evaluates their advantages and limitations. This information is valuable for researchers and readers interested in the field of organic fluorophores. The document also includes biographical information about the authors, Dr. Tapasi Chand and Dr. Manmohan Kapur. [Extracted from the article]

This article discusses the synthesis of isocoumarins using Rhodium (Rh) complexes as catalysts. The authors explore the use of phenacyl phosphoniums and iodonium ylides as building blocks in this process. They present their experimental findings, optimization of reaction conditions, and the scope of the reaction with various phenacyl phosphoniums. The research provides valuable insights into the synthesis of isocoumarins using Rh-catalyzed C-H activation. Additionally, the document provides detailed information on the synthesis and characterization of specific compounds, including their chemical structures, yields, physical properties, and spectroscopic data. [Extracted from the article]

This article discusses the development of Pd(II)-catalyzed, directing-group (DG)-mediated, site-selective functionalization of C-H bonds in small organic molecules. The focus is on the functionalization of remote C-H bonds, specifically β-C-H bonds in carboxylic acid substrates and γ-C-H bonds in amine substrates. The article provides detailed information on the reaction conditions and yields of the functionalization reactions. The text describes a study on the synthesis of arylated derivatives of phenylalaninol using a Pd(II)-catalyzed δ-C–H arylation reaction. The researchers tested different reaction conditions and directing groups to optimize the yield of the desired products. The study also explored the substrate scope by using racemic and enantiopure phenylalaninol substrates. The text describes a series of chemical reactions involving the treatment of various substrates with different aryl iodides in the presence of specific catalysts and additives. These reactions result in the formation of bis δ-C–H (ortho) arylated products, specifically phenylalaninol-based terphenyl derivatives. The reactions are performed under specific conditions and yield varying percentages of the desired products. The text also explores the extension of these reactions to enantiopure substrates and the synthesis of enantiopure bis δ-C–H (ortho) arylated products. Additionally, the text discusses attempts to perform alkylation, [Extracted from the article]

(E)- N -(2-Cyclohexyl-1-phenyl-3-(trimethylsilyl)allyl)aniline (19) General procedure A was used to react I N i -benzylaniline (183 mg, 1.0 mmol) with (cyclohexylethynyl)trimethylsilane (180 mg, 1.0 mmol) in the presence of catalyst B II-Bu b (111 mg, 0.1 mmol) for 24 h at 140 °C. Keywords: alkynes; allylamines; C-H activation; hydroaminoalkyl-ation; titanium; catalysis EN alkynes allylamines C-H activation hydroaminoalkyl-ation titanium catalysis 3759 3776 18 11/01/23 20231116 NES 231116 Graph The catalytic hydroaminoalkylation of alkenes [1][8] (Scheme 1), which takes place by a 100% atom-economical addition of the -C-H bond of a primary, [8] secondary, [8][8][8][8] or tertiary [8][8] amine across the alkene double bond, has received considerable attention over the past 15 years. N -(3,3-Dimethyl-2-methylenebutyl)aniline (1) 4d General procedure A was used to react I N i -methylaniline (107 mg, 1.0 mmol) with I tert i -butylacetylene (99 mg, 1.2 mmol) in the presence of catalyst B II-DIPP b (194 mg, 0.1 mmol) for 24 h at 140 °C. 3-Chloro- N -(3,3-dimethyl-2-methylenebutyl)aniline (5) General procedure A was used to react 3-chloro- I N i -methylaniline (142 mg, 1.0 mmol) with I tert i -butylacetylene (99 mg, 1.2 mmol) in the presence of catalyst B II-DIPP b (194 mg, 0.1 mmol) for 24 h at 140 °C. N -(3,3-Dimethyl-2-methylenebutyl)-4-(trifluoromethoxy)aniline (7) General procedure A was used to react I N i -methyl-4-(trifluoromethoxy)aniline (191 mg, 1.0 mmol) with I tert i -butylacetylene (99 mg, 1.2 mmol) in the presence of catalyst B II-DIPP b (194 mg, 0.1 mmol) for 24 h at 140 °C. [Extracted from the article]

Rh-Catalyzed Alkylation and Alkynylation of 1 with -Diazo- -keto Esters, -Diazo Esters, -D... In general, all reactions were carried out employing 50 mg of B 1 b . Rh catalysis, C-H activation, cross dehydrogenative coupling, GBT-440, diazo ester, TIPS-EBX In the context of developing new analogues of the GBT-440, one of our initial objectives was replacing the hydroxymethyl ether (which connects the pyridine and salicylaldehyde cores) with an olefin or a keto ester by pyrazole-directed C-H activation on the pyridine ring (Scheme 1, eq. 1). Keywords: Rh catalysis; C-H activation; cross dehydrogenative coupling; GBT-440; diazo ester; TIPS-EBX EN Rh catalysis C-H activation cross dehydrogenative coupling GBT-440 diazo ester TIPS-EBX 3600 3609 10 10/19/23 20231102 NES 231102 Graph Heterocyclic scaffolds like pyridine and pyrazole are the most privileged scaffolds present in many drug molecules. [Extracted from the article]

Keywords: manganese; nickel; palladium; bimetallic catalysis; indole; oxidation; C-H activation EN manganese nickel palladium bimetallic catalysis indole oxidation C-H activation 3625 3631 7 10/19/23 20231102 NES 231102 Graph I N i -Heterocyclic scaffolds are crucial in synthetic and medicinal chemistry. Subsequently, imine formation and C-H activation reaction were carried out and indole B 5a b was isolated in 19% total yield (76% yield was obtained in the C-H activation step). The filtration step seems to be crucial for the Pd-catalyzed C-H activation reaction, indicating that the presence of the Ni catalyst to a great extent inhibited the Pd-catalyzed reaction leading to a poor overall yield of the indole B 5a b . In the case of I m i -(trifluoromethyl)aniline ( B 3c b ), its corresponding imine B 4c b underwent cyclization at the less-hindered position affording 6-substituted indole B 5c b in 34% yield (yield from last step). [Extracted from the article]

SP 1 sp H NMR (400 MHz, CDCl SB 3 sb ): = 12.46 (s, 1 H), 9.12-9.10 (m, 2 H), 8.84 (dd, I J i SB 1 sb = 4.2, I J i SB 2 sb = 1.7 Hz, 1 H), 8.14-8.10 (m, 2 H), 7.62-7.58 (m, 1 H), 7.49 (dd, I J i SB 1 sb = 8.2, I J i SB 2 sb = 1.1 Hz, 1 H), 7.42-7.39 (m, 2 H), 7.32 (d, I J i = 8.1 Hz, 1 H), 7.28-7.24 (m, 1 H), 6.83 (s, 1 H), 4.29-4.23 (m, 5 H), 1.43 (t, I J i = 7.3 Hz, 3 H). SP 1 sp H NMR (400 MHz, CDCl SB 3 sb ): = 7.98 (d, I J i = 7.7 Hz, 1 H), 7.94 (dd, I J i SB 1 sb = 8.0, I J i SB 2 sb = 0.9 Hz, 1 H), 7.40-7.36 (m, 1 H), 7.33 (d, I J i = 7.8 Hz, 1 H), 7.21-7.17 (m, 1 H), 6.84-6.82 (m, 2 H), 4.27 (q, I J i = 7.2 Hz, 2 H), 3.91 (s, 3 H), 1.39 (t, I J i = 7.2 Hz, 3 H). SP 1 sp H NMR (400 MHz, CDCl SB 3 sb ): = 8.64 (s, 1 H), 8.03 (d, I J i = 7.7 Hz, 1 H), 7.41-7.37 (m, 1 H), 7.32 (d, I J i = 8.1 Hz, 1 H), 7.19-7.16 (m, 1 H), 7.12 (s, 1 H), 4.34 (q, I J i = 7.2 Hz, 2 H), 4.28 (q, I J i = 7.2 Hz, 2 H), 3.10 (t, I J i = 8.0 Hz, 2 H), 1.65-1.57 (m, 2 H), 1.40-1.35 (m, 8 H), 1.28-1.19 (m, 16 H), 0.79 (t, I J i = 6.5 Hz, 3 H). SP 1 sp H NMR (400 MHz, CDCl SB 3 sb ): = 8.70 (s, 1 H), 8.11 (d, I J i = 7.7 Hz, 1 H), 7.96-7.96 (m, 1 H), 7.93-7.90 (m, 1 H), 7.56-7.53 (m, 1 H), 7.49-7.43 (m, 2 H), 7.39 (d, I J i = 8.2 Hz, 1 H), 7.27-7.22 (m, 2 H), 4.32 (q, I J i = 7.3 Hz, 2 H), 4.08 (q, I J i = 7.2 Hz, 2 H), 2.58 (s, 3 H), 1.38 (t, I J i = 7.2 Hz, 3 H), 1.00 (t, I J i = 7.1 Hz, 3 H). [Extracted from the article]

SP 1 sp H NMR (400 MHz, CDCl SB 3 sb ): = 9.02 (s, 1 H), 8.42 (d, I J i = 7.6 Hz, 1 H), 8.14-8.10 (m, 2 H), 7.95-7.86 (m, 3 H), 7.69-7.56 (m, 3 H). SP 1 sp H NMR (400 MHz, CDCl SB 3 sb ): = 8.29 (t, I J i = 8.8 Hz, 2 H), 7.67 (s, 1 H), 7.53 (s, 1 H), 7.36 (t, I J i = 8.0 Hz, 2 H), 2.56 (s, 6 H). Keywords: C-H activation; quinazoline; heterocycle; sulfur; benzisothiazoloquinazolinone EN C-H activation quinazoline heterocycle sulfur benzisothiazoloquinazolinone 3364 3372 9 09/29/23 20231018 NES 231018 Graph Sulfur-containing compounds represent over 20% of FDA-approved drugs. SP 1 sp H NMR (400 MHz, CDCl SB 3 sb ): = 8.39 (d, I J i = 7.2 Hz, 1 H), 8.10 (d, I J i = 7.2 Hz, 1 H), 7.87 (s, 2 H), 7.70 (s, 1 H), 7.56-7.47 (m, 2 H). [Extracted from the article]

This review summarizes the more recent methods (since 2015) for the synthesis of thioethers using homogeneous metals as catalysts. The thioether moiety can be found in numerous compounds for pharmaceutical, agricultural, or material applications and it is therefore important to develop new, efficient methods for their synthesis. The recent efforts in this field focus on the use of non-precious metal catalysts, as well as on the development of new bond-forming processes. 1 Introduction 2 Cross-Couplings 3 C–H Activation 4 Hydrothiolation 5 Carbothiolation 6 Miscellaneous 7 Conclusion [ABSTRACT FROM AUTHOR]

An efficient protocol has been developed for the synthesis of larger condensed arenes from aromatic hydrocarbons and internal alkynes. This protocol uses readily available [CpRhI2 ]n as a catalyst and Cu(OAc)2 as an oxidant and proceeds smoothly through undirected double C–H activation. The addition of trifluoroacetic acid has a crucial positive impact on the reaction selectivity and the yields of the target products. In contrast to the previously reported catalytic systems, the new conditions allow the use of both dialkyl- and diarylacetylenes with the same high efficiency. [ABSTRACT FROM AUTHOR]

A new solvent/ligand-controlled switchable C–H arylation of 1-methyl-4-nitro-1 H -indazole catalyzed by Pd(OAc)2 was achieved. A bidentate ligand in DMA promoted the activation at C7 position, while a phosphine ligand in H2 O oriented the arylation at C3 position. The C3 and C7 arylation products were obtained in moderate to good yields and with high regioselectivity. [ABSTRACT FROM AUTHOR]

We herein report an eight-step asymmetric synthesis of (–)-berkelic acid. This work features a sequential Catellani-type reaction/oxa-Michael addition with epoxides as dual-functionalized alkylating reagents for synthesizing the isochroman framework, a one-pot, acid-catalyzed deprotection/spiroacetalization process for the construction of a tetracyclic core intermediate, and a late-stage Ni-catalyzed reductive coupling reaction for the installation of the side chain. Remarkably, during the deprotection/spiroacetalization process, four new stereocenters are created with high stereocontrol from a single existing chiral center. [ABSTRACT FROM AUTHOR]

A ruthenium complex with a chiral arene ligand [(camphor–arene)RuCl2 ]2 was synthesized by the reaction of RuCl3 ·nH2 O with a chiral diene which was obtained from natural camphor in three steps. This complex catalyzed the asymmetric hydrogenation of acetophenone (64–85% ee), but decomposed in catalytic reactions involving C–H activation of 2-phenylpyridine or benzoic acid derivatives. [ABSTRACT FROM AUTHOR]

Over the past decade, the combination of chiral phosphoric acid and palladium catalysis has emerged as a robust strategy to accomplish the regio- and stereoselective functionalization of inactive C–H bonds, enabling access to various types of chirality (central, planar, and axial). This review article describes the origin and advances in the asymmetric functionalization of allylic C–H, C(sp2)–H, and C(sp3)–H bonds enabled by chiral phosphoric acid and palladium combined catalysis. 1 Introduction 2.1 Enantioselective Allylic C–H Functionalization 2.2 Enantioselective Non-allylic C(sp3)–H Functionalization 2.3 Enantioselective C(sp2)–H Functionalization 3 Conclusion [ABSTRACT FROM AUTHOR]

Ruthenium(II)-catalyzed enantioselective C–H functionalization reactions of sulfoximines with sulfoxonium ylides are described. The combination of [RuCl2 (p -cymene)]2 and a pseudo- C 2-symmetric binaphthyl monocarboxylic acid furnished the S -chiral products in 76:24 to 92:8 er. [ABSTRACT FROM AUTHOR]

A variety of pyran-fused isoquinoline derivatives were prepared in moderate to good yields through the rhodium-catalyzed dual C–H functionalization/annulation of methyl benzimidates and diazo compounds. A one-pot procedure, broad substrate scope, diversified products, and mild reaction conditions make this transformation a powerful tool for the synthesis of fused heteroarenes. In addition, the synthetic application was extended by large-scale synthesis and late-stage functionalization via Pd-catalyzed Suzuki–Miyaura, Heck, and Sonogashira cross-coupling reactions. Furthermore, a photophysical survey reveals that the pyran-fused isoquinoline products exhibit fluorescence properties and show potential for exploring fluorescent material applications. [ABSTRACT FROM AUTHOR]

A palladium/norbornene-cocatalyzed Catellani-type ortho -C–H-acylation/ ipso -cyanation of iodoarenes is developed via a three-component approach using safe and low-toxic sodium carboxylates as the acyl sources and CuCN as the CN source, affording the desired products in yields of 50–94%. Without introducing a directing group on the substrate, a catalytic amount of norbornene and palladium can regioselectively activate the ortho -C–H bonds of iodoarenes. The reaction exhibits good functional group tolerance and works well on gram-scale. In addition, this transformation allows rapid and convenient access toward isoindolinones, 1,4-dicarbonyl compounds and ortho -aminated benzonitriles by manipulation of the cyano and carbonyl groups. [ABSTRACT FROM AUTHOR]

In this work, a Rh(I)-catalyzed C3-alkenylation of 2,2′-bipyri-dine-6-carboxamide with terminal and internal alkynes was developed, providing an efficient access to a broad range of alkenylated 2,2′-bipyridine derivatives with exclusive regioselectivity and stereoselectivity. Deuterium labeling experiments indicate that an irreversible rollover C–H activation process is involved in this reaction. [ABSTRACT FROM AUTHOR]

A practical method to synthesize quinoxalinones via intra/intermolecular amination using rhodium as the catalyst was developed. A wide variety of quinoxalinones were prepared from N -methoxybenzamides in moderate to excellent yields. Gram-scale reactions were also achieved, highlighting the synthetic importance of this new transformation. [ABSTRACT FROM AUTHOR]

A mild cascade annulation of Co(III)-catalyzed N -chlorobenz-amides with 2-acetylenic ketones at room temperature is reported. This reaction sets N–Cl bond of N -chlorobenzamide as an internal oxidant, displaying broad functional group tolerance and excellent reverse selectivity of alkyne insertion under mild and safe conditions. The cascade reaction offers a straightforward and mild protocol to construct isoquinolones in high yields at room temperature. [ABSTRACT FROM AUTHOR]

An iridium-catalyzed reaction protocol has been developed to achieve the oxidative C–H/N–H annulation of benzamides with cyclopropanols as C1 synthon. Structurally diverse isoindolin-1-ones were furnished via sequential C–H/C–C cleavage and C–C/C–N bond formation. [ABSTRACT FROM AUTHOR]

A Ru(II)-catalyzed synthesis of spirobi[indene]dione from phenyl indandione and alkyne is reported. This metal-catalyzed cyclization reaction proceeds through hydroxy group directed C(sp2)–H bond activation, keto–enol tautomerization and alkyne annulation pathways. [ABSTRACT FROM AUTHOR]

Sulfinic acids and their salts are a useful source of sulfur-containing structures. Photocatalysis of these compounds with visible light enables to achieve various transformations under mild conditions. This review summarizes visible-light-induced reactions of sulfinic acids and their salts. It is organized by reaction type and brief discussions on plausible reaction mechanisms for typical transformations are presented. 1 Introduction 2 Sulfonylation Reactions 2.1 Sulfonylation of Alkenes 2.2 Sulfonylation of Alkynes 2.3 Sulfonylation of Arenes 2.4 sp3 C–H Functionalization 3 Desulfonylation Reactions 4 Sulfenylation Reactions 4.1 Sulfenylation of Heteroarenes 4.2 Sulfenylation of Carbonyl Chlorides 5 Conclusions [ABSTRACT FROM AUTHOR]

The use of electricity as an inexpensive and waste-free oxidant opens up new opportunities for the development of sustainable C–H functionalization reactions. Herein we summarize recent advances in the synthesis of biaryls through electrooxidative processes involving transition-metal-catalyzed ortho -directed C–H activation. A particular focus is set on electrooxidative C–H/C–M couplings and dehydrogenative couplings. 1 Introduction 2 Electrooxidative C–H/C–M Couplings 3 Electrooxidative C–H/C–H Couplings 4 Conclusion and Outlook [ABSTRACT FROM AUTHOR]

The C–H arylation of indoles holds the promise to shorten synthetic routes in the production of pharmaceuticals. However, late-stage C–H activation reactions often rely on the presence of protecting groups or stoichiometric metal additives. The regiospecific C–H arylation of a highly functionalized azepino[5,3,4- cd ]indole scaffold lacking directing groups via Pd(II) and Cu(II) co-catalysis is reported. The direct C–H coupling was demonstrated in the convergent synthesis of rucaparib, an FDA approved anticancer drug. [ABSTRACT FROM AUTHOR]

The use of manganese triacetate as an oxidant component in the C-4 arylations of 2-aryl-quinazoline 3-oxides with arylboronic acids- is reported. The new protocol was applied to prepare new 2,4-di-arylated quinazoline 3-oxides in good to high yields. The method was shown to tolerate various substituents on both aromatic rings, and no complications such as deoxygenation or rearrangement to quinazolin-4(3 H)-one was observed. [ABSTRACT FROM AUTHOR]

In the few past years, the chemistry of frustrated Lewis pairs (FLP) has enabled a plethora of transformations that would otherwise only be possible using transition metal catalysts. Of particular interest are C–H bond activation and borylation reactions, which are the subject of this review. The FLP borylation chemistry is compared with the early borylation methodologies using strongly electrophilic borenium ions. We present the mechanism of the C–H borylation using inter- and intramolecular Lewis pairs, along with some applications of these transformations. 1 Introduction 2 Electrophilic Borylation 3 Intramolecular or Directed Electrophilic Borylation 4 Intermolecular FLP-Mediated C–H Borylation 5 Stoichiometric Borylation by Intramolecular FLPs 5.1 Csp–H Borylation 5.2 Csp2 –H Borylation 5.3 Csp3 –H Borylation 6 Catalytic Borylation by Intramolecular FLPs 7 Catalytic Borylation by Self-Assembled FLPs 8 Conclusion [ABSTRACT FROM AUTHOR]

Fluorine is well-known as a very special element. Approximately 30% of agrochemicals and 20% of all drugs contain fluorine; most of those compounds have unique functions in biochemistry, pharmacy, and bioscience and those containing alkoxycarbonyldifluoromethyl functional groups often have irreplaceable roles. Therefore, the selective introduction of alkoxycarbonyldifluoromethylated functional groups into various aromatic substrates has significant practical application. This review describes recent advances in selective alkoxycarbonyldifluoromethylation of aromatic substrates by using different catalytic strategies (cyclometalated ruthenium complex, transient regulating and visible-light-induced strategies). 1 Introduction 2 para -C–H Alkoxycarbonyldifluoromethylation of Aromatic Derivatives 2.1 Ruthenium Catalysis 2.2 Palladium Catalysis 2.3 Visible-Light Catalysis 2.4 Iron Catalysis 3 meta -C–H Alkoxycarbonyldifluoromethylation of Aromatic Derivatives 3.1 Ruthenium Catalysis 3.2 Palladium Catalysis 4 The Influence of Transition Metals and Directing Groups on Site Selectivity of Alkoxycarbonyldifluoromethylation 4.1 The Influence of Directing Groups on the Site Selectivity of Alkoxycarbonyldifluoromethylation 4.2 The Influence of Transition Metals on the Site Selectivity of Alkoxycarbonyldifluoromethylation 5 Conclusions [ABSTRACT FROM AUTHOR]

Bicyclic alkenes, including oxa- and azabicyclic alkenes, readily undergo activation with facial selectivity in the presence of transition-metal complexes. This is due to the intrinsic angle strain on the carbon–carbon double bonds in such unsymmetrical bicyclic systems. During the past decades considerable progress has been made in the area of ring opening of bicyclic strained rings by employing the concept of C–H activation. This short review comprehensively compiles the various C–H bond activation assisted reactions of oxa- and azabicyclic alkenes, viz., ring-opening reactions, hydroarylation, and annulation reactions. 1 Introduction 2 Reactions of Heterobicyclic Ring Systems 2.1 Ring-Opening Reactions of Oxa- and Azabenzonorbornadienes 2.1.1 Reactions Using 7-Oxabenzonorbornadienes 2.1.2 Reactions Using 7-Azabenzonorbornadienes 2.2 Hydroarylation Reactions 2.3 Annulation Reactions 2.4 Other Reactions 3 Conclusion [ABSTRACT FROM AUTHOR]

A cobalt-catalyzed oxidative [4+2] annulation of benz-amides with dihydrofuran was developed for the expeditious synthesis of tetrahydrofuro[2,3- c ]isoquinolinones. Commercially available and inexpensive Co(OAc)2 ·4H2 O was used as an efficient catalyst. Various functional groups were tolerated, affording the desired products in good yields with excellent regioselectivity and good diastereoselectivity under mild conditions. [ABSTRACT FROM AUTHOR]

We report a convenient method for the highly site-selective borylation of 8-arylquinoline. The reaction proceeds smoothly in the presence of a catalytic amount of [Ir(OMe)(cod)]2 and 2-phenylpyridine derived ligand using bis(pinacolato)diborane as the borylating agent. The reactions occur with high selectivity with many functional groups, providing a series of borylated 8-aryl quinolines with good to excellent yield and excellent selectivity. The borylated compounds formed in this method can be transformed into various important synthons by using known transformations. [ABSTRACT FROM AUTHOR]

Aryl rings are ubiquitous in the core of numerous natural product and industrially important molecules and thus their facile synthesis is of major interest in the scientific community and industry. Although multiple strategies enable access to these skeletons, metal-catalyzed C–H activation is promising due to its remarkable efficiency. Commercially available organoboron reagents, a prominent arylating partner in the cross-coupling domain, have also been utilized for direct arylation. Organoborons are bench-stable, inexpensive, and readily available coupling partners that promise regioselectivity, chemodivergence, cost-efficiency, and atom-economy without requiring harsh and forcing conditions. This critical, short review presents a summary of all major studies of arylation using organoborons in transition-metal catalysis since 2005. 1 Introduction 2 Arylation without Directing Group Assistance 2.1 Palladium Catalysis 2.2 Iron Catalysis 2.3 Gold Catalysis 3 Arylation with Directing Group Assistance 3.1 Palladium Catalysis 3.2 Ruthenium Catalysis 3.3 Rhodium Catalysis 3.4 Nickel Catalysis 3.5 Cobalt Catalysis 3.6 Copper Catalysis 4 Conclusion [ABSTRACT FROM AUTHOR]

We report the application of the Pd(II)-catalyzed, directing-group-aided C–H arylation/alkylation tactics to functionalize the pyrene core, especially, the relatively inaccessible C2 and K-region C10 positions of the pyrene core and augmentation of the library of pyrene derivatives with C1,C2- and C1,C10-disubstituted pyrene motifs. The Pd(II)-catalyzed β-C–H arylation/alkylation of the C2-position of pyrene-1-carboxamide possessing an 8-aminoquinoline directing group yielded various C1,C2-disubstituted pyrenes. Similarly, the Pd(II)-catalyzed selective γ-C–H arylation/alkylation of the C10-position of N -(pyren-1-yl)picolinamide, possessing a picolinamide directing group, yielded various C1,C10-disubstituted pyrenes. Examples of C(9)–H arylation of pyrene-1-carboxamide and the removal of the directing group after the C–H arylation/alkylation reactions were also shown. The structures of representative pyrene derivatives were confirmed by the X-ray structure analysis. Given the importance of the pyrene derivatives in various fields of chemical sciences, this report is a contribution towards augmentation of the library of pyrene derivatives with C1,C2- and C1,C10-disubstituted pyrene amide motifs. [ABSTRACT FROM AUTHOR]

The rhodium(I)-catalyzed reaction of alkynes with aryl-boronic acids in the presence of formaldehyde results in a CO-gas-free arylative dual-carbonylation to produce γ-butenolide derivatives. The simultaneous loading of phosphine-ligated and phosphine-free rhodium(I) complexes is required for efficient catalysis. The former complex catalyzes the abstraction of a carbonyl moiety from formaldehyde through the activation of its formyl C–H bond (decarbonylation) and the latter catalyzes the subsequent dual-incorporation of the resulting carbonyl unit (carbonylation). The use of larger amounts of the phosphine-ligated rhodium(I) complex generates more carbonyl units, leading to the formation γ-butenolides via the dual-incorporation of the carbonyl unit. [ABSTRACT FROM AUTHOR]

An efficient protocol for the palladium-catalyzed cross-coupling reaction of 2-iodobiphenyls with biphenylene has been developed through C–H activation. The reaction provides a simple and efficient method for the synthesis of unsymmetrically substituted tetra-phenylenes. [ABSTRACT FROM AUTHOR]

Strategies that enable the efficient assembly of complex building blocks from feedstock chemicals are of paramount importance to synthetic chemistry. Building upon the pioneering work of Murai and co-workers in 1993, C–H-activation-based enantioselective hydroarylations of alkenes offer a particularly promising framework for the step- and atom-economical installation of benzylic stereocenters. This short review presents recent intermolecular enantioselective Murai-type alkene hydroarylation methodologies and the mechanisms by which they proceed. 1 Introduction 2 Enantioselective Hydroarylation Reactions of Strained Bicyclic Alkenes 3 Enantioselective Hydroarylation Reactions of Electron-Rich Acyclic Alkenes 4 Enantioselective Hydroarylation Reactions of Electron-Poor Acyclic Alkenes 5 Enantioselective Hydroarylation Reactions of Minimally Polarized Acyclic Alkenes 6 Conclusion and Outlook [ABSTRACT FROM AUTHOR]

Synthetic transformations of otherwise inert C–H bonds have emerged as a powerful tool for molecular modifications during the last decades, with broad applications towards pharmaceuticals, material sciences, and crop protection. Consistently, a key challenge in C–H activation chemistry is the full control of site-selectivity. In addition to substrate control through steric hindrance or kinetic acidity of C–H bonds, one important approach for the site-selective C–H transformation of arenes is the use of chelation-assistance through directing groups, therefore leading to proximity-induced ortho -C–H metalation. In contrast, more challenging remote C–H activations at the meta - or para -positions continue to be scarce. Within this review, we demonstrate the distinct character of ruthenium catalysis for remote C–H activations until March 2021, highlighting among others late-stage modifications of bio-relevant molecules. Moreover, we discuss important mechanistic insights by experiments and computation, illustrating the key importance of carboxylate-assisted C–H activation with ruthenium(II) complexes. 1 Introduction 2 Stoichiometric Remote C–H Functionalizations 3 meta -C–H Functionalizations 4 para -C–H Functionalizations 5 meta -/ ortho -C–H Difunctionalizations 6 Conclusions [ABSTRACT FROM AUTHOR]

Aromatic C–H allylation of N -sulfonyl ketimines with allyl alcohol or allyl phenyl ether as an allyl source is catalyzed by a cationic iridium complex. The presence of a catalytic amount of a pyridine derivative was found to be essential for the reaction. In contrast, direct C–H allylation of ketimines derived from benzophenone derivatives and p -methoxyaniline with allyl phenyl ether proceeded in the absence of pyridine derivatives. [ABSTRACT FROM AUTHOR]

C–O bond formation represents a fundamental chemical transformation in organic synthesis to develop valuably oxygenated (hetero)arenes. Particularly, the direct and regioselective C–H bond oxygenation of privileged amides, using a transition metal catalyst and a mild oxygenating source, is a step-economy and attractive approach. During the last decade, considerable progress has been realized in the direct C–H oxygenation of primary, secondary, and tertiary amides. This Short Review compiles the advances in transition-metal-catalyzed oxygenation of C(sp2)–H and C(sp3)–H bonds on various amides with diverse oxygenation sources. The review is categorized into two different major sections: (i) C(sp2)–H oxygenation and (ii) C(sp3)–H oxygenation. Each section is discussed based on the directing group (monodentate and bidentate) attached to the amide derivatives. 1 Introduction 2 C(sp2)–H Oxygenation 2.1 Monodentate Directed 2.2 Bidentate Directed 3 C(sp3)–H Oxygenation 3.1 Monodentate Directed 3.2 Bidentate Directed 4 Conclusion and Outlook [ABSTRACT FROM AUTHOR]