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C–H Activation

The possibility of direct introduction of a new functionality (or a new C–C bond) via direct C–H bond transformation is a highly attractive strategy in covalent synthesis. The range of substrates is virtually unlimited, including hydrocarbons, complex organic compounds of small molecular weight, and synthetic and biological polymers. Below is a list of recent articles on this topic. For a review, see

  1. Xiao Chen, Keary M. Engle, Dong-Hui Wang, Jin-Quan Yu*
    Palladium(II)-Catalyzed C–H Activation/C–C Cross-Coupling Reactions: Versatility and Practicality
    Angew. Chem. 2009, 121, 5196–5217; Angew. Chem. Int. Ed. 2009, 48, 5094–5115

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Recent Articles

Sanjay Kumar Ghosh, Bing-Chiuan Kuo, Hsiang-Yu Chen, Jia-Ying Li, Shuang-De Liu, Hon Man Lee
Double C–H Functionalization to Construct Polycyclic Heteroarenes Catalyzed by an Ionic Salt of a Pd Complex with an N-Heterocyclic Carbene Ligand [Full Paper]

Double C–H Functionalization to Construct Polycyclic Heteroarenes Catalyzed by an Ionic Salt of a Pd Complex with an N-Heterocyclic Carbene Ligand

The complex cis-[Pd(L)(PPh3)(H2O)2](SO3CF3)2, in which L is an amido-functionalized N-heterocyclic carbene (NHC) ligand, has been prepared. This complex was effective in catalyzing the double C–H functionalization of various nitrogen- and sulfur-containing heteroarenes to form fused polycyclic heteroaromatic compounds with alkynes in the presence of Cu(OAc)2 and tetra-n-butylammonium bromide.

Eur. J. Org. Chem., May 19, 2015, DOI: 10.1002/ejoc.201500417

RhV-Nitrenoid as a Key Intermediate in RhIII-Catalyzed Heterocyclization by C-H Activation: A Computational Perspective on the Cycloaddition of Benzamide and Diazo Compounds

A calculated perspective: A mechanistic study of the 1,2,3,4,5-pentamethylcyclopentadienyl (Cp*)RhIII-catalyzed divergent cycloadditions of benzamide and diazo compounds was carried out by using DFT calculations (see scheme; Piv=pivalate; EWG=electron-withdrawing group).

Chem. Eur. J., May 15, 2015, DOI: 10.1002/chem.201500558

Ikuo Sasaki, Jumpei Taguchi, Shotaro Hiraki, Hajime Ito, Tatsuo Ishiyama
Catalyst-Controlled Regiodivergent C-H Borylation of Multifunctionalized Heteroarenes by Using Iridium Complexes [Full Paper]

Catalyst-Controlled Regiodivergent C-H Borylation of Multifunctionalized Heteroarenes by Using Iridium Complexes

Minor adjustments, major differences: The regiodivergent C-H borylation of 2,5-disubstituted heteroarenes with bis(pinacolato)diboron was achieved by using iridium catalysts formed in situ from [Ir(OMe)(cod)]2/dtbpy (cod=1,5-cyclooctadiene, dtbpy: 4,4'-di-tert-butyl-2,2'-bipyridine) or [Ir(OMe)(cod)]2/2 AsPh3 (see scheme).

Chem. Eur. J., May 12, 2015, DOI: 10.1002/chem.201500658

Cobalt(III)-Catalyzed Aryl and Alkenyl C-H Aminocarbonylation with Isocyanates and Acyl Azides

Clever cobalt: C-H aminocarbonylation of (hetero)arenes and alkenes was achieved by means of a user-friendly cobalt(III) catalyst. The reaction shows excellent chemo-, site-, and diastereoselectivity, as well as ample substrate scope.

Angew. Chem. Int. Ed., May 12, 2015, DOI: 10.1002/anie.201501926

Synthesis of Iron Hydrides by Selective C–F/C–H Bond Activation in Fluoroarylimines and Their Applications in Catalytic Reduction Reactions

The selective activation of C–H/C–F bonds was realized in the reactions of Fe(PMe3)4 with fluorophenylimines by controlling the substituents of the fluorophenylimines. Iron hydrides were obtained through C–F bond activation with the assistance of silanes. These iron hydrides show excellent catalytic activity in the hydrosilylations of aldehydes, ketones, and α,β-unsaturated aldehydes.

Eur. J. Inorg. Chem., May 11, 2015, DOI: 10.1002/ejic.201500313

Rhodium(III)-Catalyzed [4+1] Annulation of Aromatic and Vinylic Carboxylic Acids with Allenes: An Efficient Method Towards Vinyl-Substituted Phthalides and 2-Furanones

An efficient synthesis of highly substituted phthalides and 2-furanones from aryl and vinyl carboxylic acids with allenes by using a RhIII catalyst is demonstrated (see scheme). The reactions proceed through a carboxylate-assisted ortho-C-H activation and [4+1] annulation.

Chem. Eur. J., May 11, 2015, DOI: 10.1002/chem.201501106

Fang Xie, Zhipeng Zhang, Xinzhang Yu, Guodong Tang, Xingwei Li
Diaryliodoniums by Rhodium(III)-Catalyzed C-H Activation: Mild Synthesis and Diversified Functionalizations [Communication]

Diaryliodoniums by Rhodium(III)-Catalyzed C-H Activation: Mild Synthesis and Diversified Functionalizations

Bonds aplenty: Diaryliodonium salts were synthesized for the first time from electron-poor arenes by the title reaction. The diaryliodoniums can be readily functionalized by nucleophiles with high chemoselectivity, thus leading to C-C, C-S, C-N, C-P, and C-Br bond formation. Cp*=C5Me5, DG=directing group, Ts=4-toluenesulfonyl.

Angew. Chem. Int. Ed., May 8, 2015, DOI: 10.1002/anie.201502278

Tsuyoshi Oshima, Iori Yamanaka, Anupriya Kumar, Junichiro Yamaguchi, Taeko Nishiwaki-Ohkawa, Kei Muto, Rika Kawamura, Tsuyoshi Hirota, Kazuhiro Yagita, Stephan Irle, Steve A. Kay, Takashi Yoshimura, Kenichiro Itami
C-H Activation Generates Period-Shortening Molecules That Target Cryptochrome in the Mammalian Circadian Clock [Communication]

C-H Activation Generates Period-Shortening Molecules That Target Cryptochrome in the Mammalian Circadian Clock

A change in rhythm: The first functional analysis of KL001 derivatives, which are mammalian circadian-clock modulators, was enabled by cutting-edge C-H activation. The sites of the KL001 derivatives that are critical for their rhythm-changing activity were elucidated, which led to the discovery of the first period-shortening molecules that target the cryptochrome.

Angew. Chem. Int. Ed., May 8, 2015, DOI: 10.1002/anie.201502942

Kosuke Takada, Tsurugi Hanataka, Takeshi Namikoshi, Shinji Watanabe, Miki Murata
Ruthenium-Catalyzed Dehydrogenative Aromatic C-H Silylation of Benzamides with Hydrosilanes [Communication]

Karolina Graczyk, Tobias Haven, Lutz Ackermann
Iron-Catalyzed C(sp2)-H and C(sp3)-H Methylations of Amides and Anilides [Full Paper]

Iron-Catalyzed C(sp2)-H and C(sp3)-H Methylations of Amides and Anilides

Magic methyls: Expedient C-H methylations of (hetero)benzamides, alkenes, anilides, and even alkanes are realized with a broadly applicable and inexpensive iron catalyst by organometallic C(sp2)-H and C(sp3)-H activations (see scheme).

Chem. Eur. J., May 7, 2015, DOI: 10.1002/chem.201501134

Palladium-Catalyzed C2-Acylation of Indoles with α-Diketones Assisted by the Removable N-(2-Pyrimidyl) Group

A variety of 2-acylindoles were readily prepared from N-pyrimidyl-substituted indoles in moderate to good yields by an effective palladium-catalyzed C2-acylation method. The remarkable features of this methodology include good product yields and wide tolerance of various functional groups.

Eur. J. Org. Chem., May 6, 2015, DOI: 10.1002/ejoc.201500304

Divergent Reactivity in Palladium-Catalyzed Annulation with Diarylamines and α,β-Unsaturated Acids: Direct Access to Substituted 2-Quinolinones and Indoles

A basic diversion: A palladium-catalyzed C-H activation strategy is successfully employed for exclusive synthesis of 27 different 3-substituted indoles from α,β-unsaturated carboxylic acids and diarylamines under basic conditions in yields up to 89 %. Mechanistic studies revealed an ortho-palladation–π-coordination–β-migratory insertion–β-hydride elimination reaction sequence.

Chem. Eur. J., May 4, 2015, DOI: 10.1002/chem.201501208

Daniel G. Bachmann, Pascal J. Schmidt, Stefanie N. Geigle, Antoinette Chougnet, Wolf-Dietrich Woggon, Dennis G. Gillingham
Modular Ligands for Dirhodium Complexes Facilitate Catalyst Customization [Communication]

Rayavarapu Padmavathi, Rathinam Sankar, Bojan Gopalakrishnan, Ramarao Parella, Srinivasarao Arulananda Babu
Pd(OAc)2/AgOAc Catalytic System Based Bidentate Ligand Directed Regiocontrolled C–H Arylation and Alkylation of the C-3 Position of Thiophene- and Furan-2-carboxamides [Full Paper]

Pd(OAc)2/AgOAc Catalytic System Based Bidentate Ligand Directed Regiocontrolled C–H Arylation and Alkylation of the C-3 Position of Thiophene- and Furan-2-carboxamides

A contemporary method is reported for the Pd(OAc)2/AgOAc catalytic system based bidentate ligand directed, regioselective C–H activation and C–C bond formation of the C-3 position of thiophene- and furan-2-carboxamides. This protocol was used for the direct C-3 arylation and alkylation reactions of both thiophene- and furan-2-carboxamides.

Eur. J. Org. Chem., April 30, 2015, DOI: 10.1002/ejoc.201500249

Reactivity Diversification – Synthesis and Exchange Reactions of Cobalt and Iron 2-Alkenylpyridine/-pyrazine Complexes Obtained by Vinylic C(sp2)–H Activation

The regioselective cyclometalation reactions of 2-alkenylpyridine/-pyrazine derivatives with Co(CH3)(PMe3)4 provide cobalt complexes by vinylic C(sp2)–H activation. These cobalt complexes smoothly add iodomethane but readily demetalate with carbon monoxide. Conversely, reductive elimination through the release of ethane is the dominant reaction with the same ligands and Fe(CH3)2(PMe3)4.

Eur. J. Inorg. Chem., April 30, 2015, DOI: 10.1002/ejic.201500225

Vincent Vreeken, Maxime A. Siegler, Bas de Bruin, Joost N. H. Reek, Martin Lutz, Jarl Ivar van der Vlugt
C-H Activation of Benzene by a Photoactivated NiII(azide): Formation of a Transient Nickel Nitrido Complex [Communication]

C-H Activation of Benzene by a Photoactivated NiII(azide): Formation of a Transient Nickel Nitrido Complex

Triple N: Photolysis of nickel-azido complex [Ni(N3)(PNP)] (2) in benzene results in a transient NiIV nitrido species that bears significant nitridyl character, as supported by DFT calculations. Subsequent insertion of the nitrogen into a Ni-P bond, followed by Csp2-H activation of solvent yields diamagnetic [Ni(Ph)(PNPNH)] (3) featuring a parent iminophosphorane ligand. Reaction with HCl provides well-defined [Ni(Cl)(PNPNH)] (4).

Angew. Chem. Int. Ed., April 29, 2015, DOI: 10.1002/anie.201501437

Xuesong Liu, Linqian Yu, Mupeng Luo, Jidong Zhu, Wanguo Wei
Radical-Induced Metal-Free Alkynylation of Aldehydes by Direct C-H Activation [Communication]

Radical-Induced Metal-Free Alkynylation of Aldehydes by Direct C-H Activation

Direct C(sp2)-H activation of aldehyde C(O)-H bonds with hypervalent alkynyl iodides (G-EBX) provides ynones under metal-free conditions. 1-[(Triisopropylsilyl)ethynyl]-1,2-benziodoxol-3(1H)-one (TIPS-EBX) constitutes an efficient alkynylation reagent for the introduction of the triple bond.

Chem. Eur. J., April 29, 2015, DOI: 10.1002/chem.201501094

Xurong Qin, Xiaoyu Li, Quan Huang, Hu Liu, Di Wu, Qiang Guo, Jingbo Lan, Ruilin Wang, Jingsong You
Rhodium(III)-Catalyzed ortho C-H Heteroarylation of (Hetero)aromatic Carboxylic Acids: A Rapid and Concise Access to π-Conjugated Poly-heterocycles [Communication]

Rhodium(III)-Catalyzed ortho C-H Heteroarylation of (Hetero)aromatic Carboxylic Acids: A Rapid and Concise Access to π-Conjugated Poly-heterocycles

Under construction: The highly regioselective title reaction directly furnishes ortho-carboxy bi(hetero)aryls. The method has the potential to lead to the rapid construction of a library of appealing poly-heterocycles, given the complete regiocontrol, readily available substrates, and functional-group tolerance.

Angew. Chem. Int. Ed., April 27, 2015, DOI: 10.1002/anie.201501982

Isomerization of Olefins Triggered by Rhodium-Catalyzed C-H Bond Activation: Control of Endocyclic β-Hydrogen Elimination

Control of endocyclic β-H elimination of a pivotal five-membered metallacycle enables the rhodium-catalyzed isomerization of 4-pentenals into 3-pentenals without decarbonylation and leads to trans olefins with exquisite selectivity. Other sensitive olefins, even if prone to isomerization, remain intact. Endocyclic β-H elimination can also be prevented, in which case an enantiodivergent reaction on the racemic substrate was observed.

Angew. Chem. Int. Ed., April 23, 2015, DOI: 10.1002/anie.201500596

Asymmetric Nickel-Catalysed Cross-Hydrovinylation of Two Terminal Alkenes

Pushing the boundaries: The asymmetric 1,2-hydrovinylation of styrene derivatives with terminal alkenes is realised by using a nickel catalyst and specially designed chiral NHC ligands to achieve a new level of complexity for the tail-to-tail cross-coupling of alkenes by C-H activation.

ChemCatChem, April 20, 2015, DOI: 10.1002/cctc.201500177

Regioselective Syntheses of 1,2-Benzothiazines by Rhodium-Catalyzed Annulation Reactions

Domino effect: Rhodium-catalyzed annulation reactions provide 1,2-benzothiazines in excellent yields starting from S-aryl sulfoximines and diazo compounds. The catalysis shows a high functional-group tolerance and the process demonstrates excellent regioselectivity.

Angew. Chem. Int. Ed., April 14, 2015, DOI: 10.1002/anie.201501583

Ai-Hua Zhou, Fei Pan, Chunyin Zhu, Long-Wu Ye
Recent Progress towards Transition Metal-Catalyzed Synthesis of Fluorenes [Minireview]

Recent Progress towards Transition Metal-Catalyzed Synthesis of Fluorenes

Fluorene structures are commonly encountered in materials science, pharmaceutical chemistry, and organic synthesis. This Minireview summarizes how transition metal catalysis has become the prevalent strategy for the synthesis of fluorenes, as highlighted by examples from throughout the last decade.

Chem. Eur. J., April 9, 2015, DOI: 10.1002/chem.201500545

Alexandre Vasseur, Jacques Muzart, Jean Le Bras
Ubiquitous Benzoquinones, Multitalented Compounds for Palladium-Catalyzed Oxidative Reactions [Microreview]

Ubiquitous Benzoquinones, Multitalented Compounds for Palladium-Catalyzed Oxidative Reactions

This review highlights the multifaceted properties of benzoquinone when it is involved in PdII-catalyzed oxidative reactions and presents mechanisms proposed in the literature.

Eur. J. Org. Chem., March 30, 2015, DOI: 10.1002/ejoc.201500080

Sara Ruiz, Pedro Villuendas, Manuel A. Ortuño, Agustí Lledós, Esteban P. Urriolabeitia
Ruthenium-Catalyzed Oxidative Coupling of Primary Amines with Internal Alkynes through C-H Bond Activation: Scope and Mechanistic Studies [Full Paper]

Ruthenium-Catalyzed Oxidative Coupling of Primary Amines with Internal Alkynes through C-H Bond Activation: Scope and Mechanistic Studies

Efficiency of ruthenium: The oxidative coupling of primary amines with internal alkynes catalyzed by Ru complexes is presented as a general atom-economical methodology with a broad scope of applications in the synthesis of N-heterocycles (see figure). DFT calculations support a reaction mechanism that consists of acetate-assisted C-H bond activation, migratory-insertion, and C-N bond-formation steps.

Chem. Eur. J. 2015, 21, No. 23, 8626-8636

Palladium-Catalyzed [3+3] Annulation between Diarylamines and α,β-Unsaturated Acids through C-H Activation: Direct Access to 4-Substituted 2-Quinolinones

4-Substituted 2-quinolinone species were synthesized in high yields by a palladium-catalyzed dehydrogenative coupling involving diarylamines. This intermolecular annulation approach incorporates readily available α,β-unsaturated carboxylic acids as the coupling partner by suppressing decarboxylation.

Chem. Eur. J. 2015, 21, No. 23, 8360-8364

Kenta Saito, Prasanna Kumara Chikkade, Motomu Kanai, Yoichiro Kuninobu
Palladium-Catalyzed Construction of Heteroatom-Containing π-Conjugated Systems by Intramolecular Oxidative C-H/C-H Coupling Reaction [Communication]

Palladium-Catalyzed Construction of Heteroatom-Containing π-Conjugated Systems by Intramolecular Oxidative C-H/C-H Coupling Reaction

Up the ladder: Synthesis of heteroatom-containing ladder-type π-conjugated molecules was successfully achieved via palladium-catalyzed intramolecular oxidative C-H/C-H cross-coupling reaction (see scheme). This reaction provides a variety of π-conjugated molecules bearing heteroatoms, such as nitrogen, oxygen, phosphorus, and sulfur atoms, and a carbonyl group.

Chem. Eur. J. 2015, 21, No. 23, 8365-8368

Palladium(0)/PAr3-Catalyzed Intermolecular Amination of C(sp3)-H Bonds: Synthesis of β-Amino Acids

Zero in: The title reaction begins with oxidative addition of R2N-OBz to a Pd0/PAr3 catalyst and subsequent cleavage of a C(sp3)-H bond by the generated Pd-NR2 intermediate. The catalytic cycle proceeds without the need for external oxidants. The electron-deficient triarylphosphine ligand is crucial for this C(sp3)-H amination reaction to occur. Bz=benzoyl.

Angew. Chem. Int. Ed. 2015, 54, No. 22, 6545-6549

Natsuyo Kamimoto, Dieter Schollmeyer, Koichi Mitsudo, Seiji Suga, Siegfried R. Waldvogel
Palladium-Catalyzed Domino C-H/N-H Functionalization: An Efficient Approach to Nitrogen-Bridged Heteroacenes [Full Paper]

Palladium-Catalyzed Domino C-H/N-H Functionalization: An Efficient Approach to Nitrogen-Bridged Heteroacenes

Extended heteroacenes: A twofold arylation protocol for the efficient synthesis of 9H-benzo[4,5]thieno[3,2-b]thieno[3,4-d]pyrroles and 10H-benzo[4,5]thieno[3,2-b]indoles was developed (see scheme). The selectivity of this novel sequence allows the construction of highly π-extended heteroacenes.

Chem. Eur. J. 2015, 21, No. 22, 8257-8261

Stephen P. Cooper, Kevin I. Booker-Milburn
A Palladium(II)-Catalyzed C-H Activation Cascade Sequence for Polyheterocycle Formation [Communication]

A Palladium(II)-Catalyzed C-H Activation Cascade Sequence for Polyheterocycle Formation

Don't overdo it: A palladium(II)-catalyzed C-H activation cascade sequence for the synthesis of polyheterocycles is reported. Aromatization of the initially formed dihydro species occurred with a quinone oxidant. In some cases the use of one equivalent of the oxidant enabled isolation of the dihydro species as a single isomer (see scheme; X=NMe, O, S).

Angew. Chem. Int. Ed. 2015, 54, No. 22, 6496-6500

Intermolecular C-H Bond Activation by a Cationic Iridium(III) Dichloride Phenanthroline Complex

Iridium(III) unleashed: A cationic phenanthroline complex of IrIII can cleave C-H bonds of unactivated secondary carbons as well as benzylic carbons but not bonds to sp2 or primary carbons in the gas phase. The unique reactivity pattern likely stems from the suboptimum bite angle provided by the phenanthroline ligand. Computational modeling suggests that the C-H activation process is concerted, without a stable oxidative addition intermediate.

Angew. Chem. Int. Ed. 2015, 54, No. 22, 6475-6478

Raphaël Rochat, Koji Yamamoto, Michael J. Lopez, Haruki Nagae, Hayato Tsurugi, Kazushi Mashima
Organomagnesium-Catalyzed Isomerization of Terminal Alkynes to Allenes and Internal Alkynes [Full Paper]

Organomagnesium-Catalyzed Isomerization of Terminal Alkynes to Allenes and Internal Alkynes

Selective and important: Magnesium complexes bearing aminoamido ligands are precursors for the isomerization of terminal alkynes to allenes and further to internal alkynes through temporally separated autotandem catalysis (see picture). The catalytically active tetraalkynyl complexes consist of a tautomeric mixture of alkynyl-, allenyl-, and propargylmagnesium species.

Chem. Eur. J. 2015, 21, No. 22, 8112-8120

Shinsuke Okada, Takeshi Namikoshi, Shinji Watanabe, Miki Murata
Ruthenium-Catalyzed Ortho-Selective Aromatic C-H Borylation of 2-Arylpyridines with Pinacolborane [Communication]

Ruthenium-Catalyzed Ortho-Selective Aromatic C-H Borylation of 2-Arylpyridines with Pinacolborane

A ruthenium for C-H borylation: The ruthenium-catalyzed dehydrogenative borylation of 2-arylpyridines with pinacolborane took place at ortho-positions of the benzene ring.

ChemCatChem 2015, 7, No. 10, 1531-1534

Stefano Protti, Maurizio Fagnoni, Davide Ravelli
Photocatalytic C-H Activation by Hydrogen-Atom Transfer in Synthesis [Minireview]

Photocatalytic C-H Activation by Hydrogen-Atom Transfer in Synthesis

HATs off to photocatalysis! This review covers the recent advancements in the field of photocatalytic hydrogen-atom transfer (HAT) processes for C-H bond functionalization. Applications in organic synthesis, including the formation of C-C, as well as C-halogen, C-O (C=O) and C-N bonds, are presented.

ChemCatChem 2015, 7, No. 10, 1516-1523

Marc Moselage, Nicolas Sauermann, Sven C. Richter, Lutz Ackermann
C-H Alkenylations with Alkenyl Acetates, Phosphates, Carbonates, and Carbamates by Cobalt Catalysis at 23 °C [Communication]

C-H Alkenylations with Alkenyl Acetates, Phosphates, Carbonates, and Carbamates by Cobalt Catalysis at 23 °C

Inexpensive cobalt catalysis enabled the C-H alkenylation of unactivated (hetero)arenes with enol derivatives at ambient temperature. The versatile cobalt catalyst was employed for challenging C-H/C-O cleavage reactions with alkenyl acetates, carbamates, carbonates, and phosphates in a stereoconvergent fashion.

Angew. Chem. Int. Ed. 2015, 54, No. 21, 6352-6355

Zi-Qi Lin, Wei-Zhen Wang, Shao-Bai Yan, Wei-Liang Duan
Palladium-Catalyzed Enantioselective C-H Arylation for the Synthesis of P-Stereogenic Compounds [Communication]

Palladium-Catalyzed Enantioselective C-H Arylation for the Synthesis of P-Stereogenic Compounds

Dressing up phosphorus: The title reaction of N-(o-bromoaryl)-diarylphosphinic amides is described for the synthesis of phosphorus compounds bearing a P-stereogenic center. The method provides good enantioselectivities and high yields. The products were readily transformed into P-chiral biphenyl monophosphine ligands.

Angew. Chem. Int. Ed. 2015, 54, No. 21, 6265-6269

Gabriel Theurkauff, Arnaud Bondon, Vincent Dorcet, Jean-François Carpentier, Evgueni Kirillov
Heterobi- and -trimetallic Ion Pairs of Zirconocene-Based Isoselective Olefin Polymerization Catalysts with AlMe3 [Communication]

Heterobi- and -trimetallic Ion Pairs of Zirconocene-Based Isoselective Olefin Polymerization Catalysts with AlMe3

Zirconocene-based AlMe3 adducts bind an additional AlMe3 molecule reversibly, affording heterotrimetallic intermediates. One of the AlMe3 adducts undergoes slow decomposition via C-H activation in a bridging methyl unit to yield a new species with a trimetallic {Zr(μ-CH2)(μ-Me)AlMe(μ-Me)AlMe2} core.

Angew. Chem. Int. Ed. 2015, 54, No. 21, 6343-6346

Jin Xie, Shuai Shi, Tuo Zhang, Nina Mehrkens, Matthias Rudolph, A. Stephen K. Hashmi
A Highly Efficient Gold-Catalyzed Photoredox α-C(sp3)-H Alkynylation of Tertiary Aliphatic Amines with Sunlight [Communication]

A Highly Efficient Gold-Catalyzed Photoredox α-C(sp3)-H Alkynylation of Tertiary Aliphatic Amines with Sunlight

Golden sunshine: With 1-iodoalkynes as radical alkynylation reagents, unactivated tertiary aliphatic amines react in the presence of [Au2(μ-dppm)2]2+ (dppm=bis(diphenylphosphanyl)methane) in sunlight to afford propargylamines. A C-C coupling of an α-aminoalkyl radical and an alkynyl radical was proposed as the mechanism.

Angew. Chem. Int. Ed. 2015, 54, No. 20, 6046-6050

Palladium-Catalyzed C-H Activation of N-Allyl Imines: Regioselective Allylic Alkylations to Deliver Substituted Aza-1,3-Dienes

Making one into two: Palladium-catalyzed direct C(sp3)-H activation of an N-allyl imine led to the generation of an all-carbon π-allyl complex which presumably remains in equilibrium with a rare 2-aza π-allyl species. Nucleophilic attack on the π-allyl intermediates gave either a 1-aza-1,3-diene or 2-aza-1,3-diene in a completely regioselective manner.

Angew. Chem. Int. Ed. 2015, 54, No. 20, 6032-6036

Rhodium(I)-Catalyzed Regiospecific Dimerization of Aromatic Acids: Two Direct C-H Bond Activations in Water

On the double: An efficient, regiospecific, and general oxidative dimerization of simple aryl acids to generate diaryl acids was developed. The reaction involves two direct aryl C-H activations catalyzed by rhodium, uses water as the solvent, and can be easily scaled up. The natural product ellagic acid was obtained in only two steps by using this method.

Angew. Chem. Int. Ed. 2015, 54, No. 19, 5718-5721

Linda S. Jongbloed, Bas de Bruin, Joost N. H. Reek, Martin Lutz, Jarl Ivar van der Vlugt
Facile Synthesis and Versatile Reactivity of an Unusual Cyclometalated Rhodium(I) Pincer Complex [Full Paper]

Facile Synthesis and Versatile Reactivity of an Unusual Cyclometalated Rhodium(I) Pincer Complex

MC Flex: A flexidentate PN(C) scaffold amenable to acting as either a bi- or tridentate ligand to a RhI center is described. Tridentate coordination involves facile aromatic C-H activation to generate a rare low-valent RhI metallacycle. The formation of a C-H agostic complex, dual-mode ligand reactivity, and the synthesis of the corresponding RhIII–diiodide complex is discussed.

Chem. Eur. J. 2015, 21, No. 19, 7297-7305

Tandem Catalytic C(sp3)-H Amination/Sila-Sonogashira–Hagihara Coupling Reactions with Iodine Reagents

I(003) is a double agent: A tandem C-N and C-C bond-forming reaction has been achieved through RhII/Pd0 catalysis. The sequence first involves an iodine(III) oxidant, then the in situ generated iodine(I) by-product is used as a coupling partner. The overall process affords complex building blocks with high yields, and demonstrates the synthetic value of iodoarenes produced in trivalent iodine reagent mediated oxidations.

Angew. Chem. Int. Ed. 2015, 54, No. 19, 5697-5701

Ruthenium as a Single Catalyst for Two Steps: One-Pot Ruthenium(II)-Catalyzed Aerobic Oxidative Dehydrogenation of Dihydroquinazolinones and Cross-Coupling/Annulation to give N-Fused Polycyclic Heteroarenes

One catalyst fits all: One single catalyst, [RuCl2(p-cymene)]2, was used for oxidative dehydrogenation followed by cross-coupling/annulation reactions to access diversely decorated N-fused polycyclic heteroarenes from dihydroquinazolinones and alkynes. DCE=1,2-dichloroethane.

Asian J. Org. Chem. 2015, 4, No. 05, 462-469

Werner Uhl, Anne Hentschel, Dirk Kovert, Jutta Kösters, Marcus Layh
Heterocyclic Digallanates, Encapsulation of Lithium Cations in Organometallic Cages and C–H Bond Activation [Full Paper]

Heterocyclic Digallanates, Encapsulation of Lithium Cations in Organometallic Cages and C–H Bond Activation

C–H bond activation and ortho-metallation was achieved by heating novel macrocyclic phenylene centered dilithium di(galliumalkenyl) compounds in solution. The products contained five-membered GaC4 heterocycles. Various Li–π interactions resulted in fascinating molecular structures for the digallanate intermediates and the finally isolated metallacycles.

Eur. J. Inorg. Chem. 2015, No. 14, 2486-2496

Ebrahim Kianmehr, Mehrdad Torabi, Mehran Rezazadeh Khalkhali, Nasser Faghih, Khalid Mohammed Khan
Palladium-Catalyzed Regioselective Cross-Dehydrogenative Coupling of Benzofurans with Uracils at Room Temperature [Short Communication]

Palladium-Catalyzed Regioselective Cross-Dehydrogenative Coupling of Benzofurans with Uracils at Room Temperature

The Pd-catalyzed cross-dehydrogenative coupling (CDC) between two heteroarenes is developed. A variety of benzofuran and uracil derivatives are constructed in good yields with good regioselectivity at room temperature through C–C bond formation by using CDC reactions; prefunctionalization of the substrates is not required. PivOH = pivalic acid.

Eur. J. Org. Chem. 2015, No. 13, 2796-2800

Ganesh Chandra Nandi, Sudhakar Rao Kota, Tricia Naicker, Thavendran Govender, Hendrick G. Kruger, Per I. Arvidsson
Cu(OAc)2-Catalysed Oxidative Dual C–H/N–H Activation of Terminal Alkynes and N-Deprotected Sulfonimidamides: An Easy Access to N-Alkynylated Sulfonimidamides [Full Paper]

Cu(OAc)2-Catalysed Oxidative Dual C–H/N–H Activation of Terminal Alkynes and N-Deprotected Sulfonimidamides: An Easy Access to N-Alkynylated Sulfonimidamides

N-Alkynylated sulfonimidamides have been synthesised through the CuII-catalysed N–H/C–H activation reaction of N-deprotected sulfonimidamides and terminal alkynes. The resulting N-alkynylated sulfonimidamides react with SiO2 or BH3·SMe2 to give the corresponding carbonyl or alkyl derivative, respectively.

Eur. J. Org. Chem. 2015, No. 13, 2861-2867

Svenja Warratz, Christoph Kornhaaß, Ana Cajaraville, Benedikt Niepötter, Dietmar Stalke, Lutz Ackermann
Ruthenium(II)-Catalyzed C-H Activation/Alkyne Annulation by Weak Coordination with O2 as the Sole Oxidant [Communication]

Ruthenium(II)-Catalyzed C-H Activation/Alkyne Annulation by Weak Coordination with O2 as the Sole Oxidant

Air and water: Ruthenium(II) biscarboxylates allow for the annulation of alkynes and alkenes by oxidative C-H functionalizations with molecular oxygen as the sole oxidant. The C-H/O-H functionalization process occurs with excellent selectivities under mild reaction conditions, with water produced as the only by-product.

Angew. Chem. Int. Ed. 2015, 54, No. 18, 5513-5517

Synthesis of Dibenzo[c,e]oxepin-5(7H)-ones from Benzyl Thioethers and Carboxylic Acids: Rhodium-Catalyzed Double C-H Activation Controlled by Different Directing Groups

Double crossed! Reported is the rhodium(III)-catalyzed double C-H cross-coupling of benzyl thioethers and carboxylic acids. Two directing groups (DGs) are used to enhance the selectivity of the double C-H activation. One DG becomes part of the product and the other is removed in situ.

Angew. Chem. Int. Ed. 2015, 54, No. 18, 5478-5482

Leung Gulice Yiu Chung, Nur Asyikin Binte Juwaini, Jayasree Seayad
Palladium-Catalyzed Oxidative Heck Coupling of Cyclic Enones with Simple Arenes by C-H Activation [Communication]

Palladium-Catalyzed Oxidative Heck Coupling of Cyclic Enones with Simple Arenes by C-H Activation

For the Heck of it: A simple catalyst system consisting of Pd(OAc)2 and 3-nitropyridine for the aerobic oxidative Heck coupling of challenging unsubstituted cyclic enones with simple arenes by C-H activation is reported. This method is applicable to various substituted arenes and cyclic enones and allows the synthesis of a range of β-aryl cyclic enones.

ChemCatChem 2015, 7, No. 08, 1270-1274

Jilai Li, Xiao-Nan Wu, Maria Schlangen, Shaodong Zhou, Patricio González-Navarrete, Shiya Tang, Helmut Schwarz
On the Role of the Electronic Structure of the Heteronuclear Oxide Cluster [Ga2Mg2O5].+ in the Thermal Activation of Methane and Ethane: An Unusual Doping Effect [Communication]

On the Role of the Electronic Structure of the Heteronuclear Oxide Cluster [Ga2Mg2O5].+ in the Thermal Activation of Methane and Ethane: An Unusual Doping Effect

Bridging oxygen: A combination of mass spectrometry and quantum chemical calculations shows that [Ga2Mg2O5].+, bearing an unpaired electron at a bridging oxygen atom, is capable of activating the C-H bond of methane. The roles of spin density and charge distributions in hydrogen-atom transfer processes provide important guidance for the rational design of catalysts.

Angew. Chem. Int. Ed. 2015, 54, No. 17, 5074-5078

Synthesis of a Double Helicene by a Palladium-Catalyzed Cross-Coupling Reaction: Structure and Physical Properties

Do the twist again! A twisted π-extended double helicene was synthesized through a palladium-catalyzed coupling reaction. X-ray crystallography revealed grossly twisted structures that were soluble in various conventional organic solvents. Electrochemical properties were also studied by measurements of cyclic voltammetry, which revealed its HOMO and LUMO energies (see scheme).

Chem. Eur. J. 2015, 21, No. 17, 6523-6527

Neeraj Kumar Mishra, Taejoo Jeong, Satyasheel Sharma, Youngmi Shin, Sangil Han, Jihye Park, Joa Sub Oh, Jong Hwan Kwak, Young Hoon Jung, In Su Kim
Rhodium(III)-Catalyzed Selective C-H Cyanation of Indolines and Indoles with an Easily Accessible Cyano Source [Update]

Peter Finkbeiner, Ulrich Kloeckner, Boris J. Nachtsheim
OH-Directed Alkynylation of 2-Vinylphenols with Ethynyl Benziodoxolones: A Fast Access to Terminal 1,3-Enynes [Communication]

OH-Directed Alkynylation of 2-Vinylphenols with Ethynyl Benziodoxolones: A Fast Access to Terminal 1,3-Enynes

TIPS and tricks for alkynylation: The first direct alkynylation of 2-vinylphenols was developed. The rationally optimized hypervalent iodine reagent TIPS-EBX* (see scheme) in combination with [(Cp*RhCl2)2] as a C-H-activating transition-metal catalyst enables the construction of a variety of highly substituted 1,3-enynes in high yield under mild conditions and with excellent chemo- and stereoselectivity.

Angew. Chem. Int. Ed. 2015, 54, No. 16, 4949-4952

A General and Scalable Synthesis of Aeruginosin Marine Natural Products Based on Two Strategic C(sp3)-H Activation Reactions

Family ties: An efficient access to the aeruginosin family of marine natural products, which exhibit potent inhibitory activity against serine proteases, was achieved. The strategic use of two different C(sp3)-H activation reactions led to the synthesis of aeruginosins 98B and 298 A, with the latter being obtained on an unprecedentedly large scale.

Angew. Chem. Int. Ed. 2015, 54, No. 16, 4919-4922

Ning Jin, Changduo Pan, Honglin Zhang, Pan Xu, Yixiang Cheng, Chengjian Zhu
Rhodium-Catalyzed Direct C7 Alkynylation of Indolines [Communication]

Gang Li, Chunqi Jia, Qingliang Chen, Kai Sun, Feng Zhao, Hankui Wu, Zhiyong Wang, Yunhe Lv, Xiaolan Chen
Copper(I)-Catalyzed Dehydrogenative Amidation of Arenes Using Air as the Oxidant [Update]

Pd-Catalyzed C-H Activation: Expanding the Portfolio of Metal-Catalyzed Functionalization of Unreactive C-H Bonds by Arene–Chromium π-Complexation

Switch it on: η6-arene–transition-metal complexes are significant intermediates in organic chemistry; however, their use in C-H functionalization remain largely unexplored. Recently, new methodologies for the Pd-catalyzed C-H activation of unreactive sp2 and sp3 bonds that rely on the efficient activation of arenes by π-complexation have been developed. These reactions significantly expand the toolbox of modern C-H activation methods.

ChemCatChem 2015, 7, No. 07, 1061-1063

Lara Ferrighi, Igor Píš, Thanh Hai Nguyen, Mattia Cattelan, Silvia Nappini, Andrea Basagni, Matteo Parravicini, Antonio Papagni, Francesco Sedona, Elena Magnano, Federica Bondino, Cristiana Di Valentin, Stefano Agnoli
Control of the Intermolecular Coupling of Dibromotetracene on Cu(110) by the Sequential Activation of C-Br and C-H Bonds [Full Paper]

Control of the Intermolecular Coupling of Dibromotetracene on Cu(110) by the Sequential Activation of C-Br and C-H Bonds

Scratching the surface: Easy control of the intermolecular coupling of 5,11-dibromotetracene on a Cu(110) surface by temperature has been achieved. Organometallic oligomers characterized by copper atoms that bridge the tetracene molecule in the 5,11 positions are formed at mild temperature (room temperature to 523 K), whereas the higher intrinsic stability of the radical sites at the 3,2 and 8,9 positions determines the formation of linear chains produced by C-C coupling between the ends of the molecules at higher temperature (see picture).

Chem. Eur. J. 2015, 21, No. 15, 5826-5835

Cobalt-Catalyzed C-H Arylations with Weakly-Coordinating Amides and Tetrazoles: Expedient Route to Angiotensin-II-Receptor Blockers

Broadly applicable cobalt-catalyzed C-H arylations with weakly-coordinating amides or tetrazoles provided step-economical access to biaryl tetrazoles as key structural motifs of angiotensin-II-receptor blockers (ARBs), such as the blockbuster drug Losartan (see scheme).

Chem. Eur. J. 2015, 21, No. 15, 5718-5722

Transition-Metal-Catalyzed π-Bond-Assisted C-H Bond Functionalization: An Emerging Trend in Organic Synthesis

Piece of pi: Transition-metal-catalyzed directing-group-assisted C-H activation reactions play an indispensable role in organic synthesis. Most directing groups interact with metals through the σ coordination of their lone pairs, yet π-bond directing groups also exist (see figure). The π-coordination-assisted C-H bond functionalization reactions are summarized.

Chem. Asian J. 2015, 10, No. 04, 824-838

Feihua Luo, Jun Yang, Zhengkai Li, Haifeng Xiang, Xiangge Zhou
Palladium-Catalyzed C–H Bond Acylation of Acetanilides with Benzylic Alcohols under Aqueous Conditions [Full Paper]

Palladium-Catalyzed C–H Bond Acylation of Acetanilides with Benzylic Alcohols under Aqueous Conditions

Palladium-catalyzed dehydrogenative coupling reactions between acetanilides and benzylic alcohols under aqueous conditions are reported. A wide range of benzophenone derivatives could be obtained in good to excellent yields up to 98 %. Mechanism studies showed that a bimetallic palladium cyclopalladated complex might be involved in the catalysis.

Eur. J. Org. Chem. 2015, No. 11, 2463-2469

Manfred Manßen, Nicolai Lauterbach, Jaika Dörfler, Marc Schmidtmann, Wolfgang Saak, Sven Doye, Rüdiger Beckhaus
Efficient Access to Titanaaziridines by C-H Activation of N-Methylanilines at Ambient Temperature [Communication]

Efficient Access to Titanaaziridines by C-H Activation of N-Methylanilines at Ambient Temperature

Killing two birds with one stone: A bis(η51-pentafulvene)titanium complex reacts with secondary N-methylamines resulting in simultaneous N-H and C-H activation and formation of titanaaziridines. These reactions can even be performed below room temperature und generate three-membered titanacycles. The first molecular structure of a titanium methyleneaniline complex is determined.

Angew. Chem. Int. Ed. 2015, 54, No. 14, 4383-4387

Hao Wu, Zhiwei Xiao, Junhui Wu, Yong Guo, Ji-Chang Xiao, Chao Liu, Qing-Yun Chen
Direct Trifluoromethylthiolation of Unactivated C(sp3)-H Using Silver(I) Trifluoromethanethiolate and Potassium Persulfate [Communication]

Direct Trifluoromethylthiolation of Unactivated C(sp3)-H Using Silver(I) Trifluoromethanethiolate and Potassium Persulfate

Direct and mild: A variety of alkyltrifluoromethylthioethers were efficiently synthesized by direct trifluoromethylthiolation of unactivated C(sp3)-H bonds under mild reaction conditions. The reagent system comprises AgSCF3 and K2S2O8, the latter of which both activates the C(sp3)-H bond and oxidizes AgSCF3. The reaction has a broad substrate scope with good functional-group tolerance and good selectivity.

Angew. Chem. Int. Ed. 2015, 54, No. 13, 4070-4074

Shuaibo Guo, Yaxuan Li, Yu Wang, Xin Guo, Xu Meng, Baohua Chen
Iron-Catalyzed Cross Dehydrogenative Coupling (CDC) of Indoles and Benzylic C-H Bonds [Communication]

Shuo Guo, Xiaofei Zhang, Pingping Tang
Silver-Mediated Oxidative Aliphatic C-H Trifluoromethylthiolation [Communication]

Silver-Mediated Oxidative Aliphatic C-H Trifluoromethylthiolation

The silver-mediated trifluoromethylthiolation of unactivated aliphatic C-H bonds is reported. The reaction is operationally simple, amenable to gram-scale synthesis, and can be employed for the late-stage trifluoromethylthiolation of complex small molecules.

Angew. Chem. Int. Ed. 2015, 54, No. 13, 4065-4069

Alexander W. Jones, Marie-Laure Louillat-Habermeyer, Frederic W. Patureau
Strained Dehydrogenative Ring Closure of Phenylcarbazoles [Communication]

Irwan Iskandar Roslan, Jiulong Sun, Gaik-Khuan Chuah, Stephan Jaenicke
Cobalt(II)-Catalyzed Electrophilic Alkynylation of 1,3-Dicarbonyl Compounds To Form Polysubstituted Furans via π–π Activation [Communication]

Cp*CoIII-Catalyzed C-H Activation of (Hetero)arenes: Expanding the Scope of Base-Metal-Catalyzed C-H Functionalizations

Directed activation: Cationic Cp*CoIII (Cp*=1,2,3,4,5-pentamethylcyclopentadienyl) complexes, either well-defined or in situ-generated, promote catalytic functionalization of arene C-H bonds with a variety of electrophilic reaction partners by directed C-H activation. These complexes not only emulate known reaction patterns of Cp*RhIII analogues, but also exhibit remarkable catalytic activity or unique reactivity. DG=Directing group.

ChemCatChem 2015, 7, No. 05, 732-734

Youngmi Shin, Satyasheel Sharma, Neeraj Kumar Mishra, Sangil Han, Jihye Park, Hyunji Oh, Jimin Ha, Hyunwu Yoo, Young Hoon Jung, In Su Kim
Direct and Site-Selective Palladium-Catalyzed C-7 Acylation of Indolines with Aldehydes [Update]

Norbert Hoffmann
Combining Photoredox and Metal Catalysis [Highlight]

Combining Photoredox and Metal Catalysis

A photogenic pair: Photoredox catalysis with visible light and molecular oxygen as oxidant in combination with palladium catalysis enables highly efficient activation of C-H bonds. Mild photochemical reaction conditions generally facilitate the combination of different catalytic reactions.

ChemCatChem 2015, 7, No. 03, 393-394

Yasutomo Segawa, Takehisa Maekawa, Kenichiro Itami
Synthesis of Extended π-Systems through C–H Activation [Review]

Synthesis of Extended π-Systems through C–H Activation

By no means π in the sky! The activation of aromatic C-H bonds by a transition metal catalyst has received significant attention in the synthetic chemistry community. In recent years, rapid and site-selective extension of π-electron systems by C–H activation has emerged as an ideal methodology for preparing conjugated organic materials. This Review focuses on recent developments in this area directed toward new optoelectronic materials.

Angew. Chem. Int. Ed. 2015, 54, No. 01, 66-81

Rongwei Jin, Frederic W. Patureau
Metal-free Dehydrogenative Isoquinolone Synthesis [Highlight]

Metal-free Dehydrogenative Isoquinolone Synthesis

Versatile C-H bonds: We discuss Manna and Antonchick's metal-free isoquinolone synthesis through the dehydrogenative condensation of benzamides with alkynes and what it means for the fields of C-H functionalization and organic synthesis. DG=Directing group, E=electrophile.

ChemCatChem 2015, 7, No. 02, 223-225

Malek Nechab, Shovan Mondal, Michèle P. Bertrand
1,n-Hydrogen-Atom Transfer (HAT) Reactions in Which n≠5: An Updated Inventory [Review]

1,n-Hydrogen-Atom Transfer (HAT) Reactions in Which n≠5: An Updated Inventory

Intramolecular HAT scope: The investigation of the less commonly encountered 1,n-hydrogen-atom transfer (HAT) reactions in which n≠5 has led to high yielding original synthetic applications. The aim of this Review is to make a critical updated inventory, highlighting the most elegant cascade reactions based on a 1,n-HAT elementary step (from A to B) in which n=4, 6, 7, 8, 9, and so forth.

Chem. Eur. J. 2014, 20, No. 49, 16034-16059

Matthijs Ruitenbeek, Bert M. Weckhuysen
A Radical Twist to the Versatile Behavior of Iron in Selective Methane Activation [Highlight]

A Radical Twist to the Versatile Behavior of Iron in Selective Methane Activation

Things go better without coke! The selective activation of methane and its direct conversion into light olefins and aromatic compounds remains a formidable challenge. Recent work shows that a catalyst material consisting of lattice-confined single iron atoms is very active and selective in the direct, nonoxidative conversion of methane into ethylene, benzene, and naphthalene without the formation of coke deposits.

Angew. Chem. Int. Ed. 2014, 53, No. 42, 11137-11139

Niles J. Gunsalus, Michael M. Konnick, Brian G. Hashiguchi, Roy A. Periana
Discrete Molecular Catalysts for Methane Functionalization [Review]

Rowan D. Young
Characterisation of Alkane σ-Complexes [Minireview]

Characterisation of Alkane σ-Complexes

The coordination of alkanes to metal centers is a complex matter! Advances in synthetic strategies to produce alkane σ-complexes, and ever more detailed analyses of such complexes, is leading to an understanding of how alkanes bind to specific metal centers. Such analysis is vital in understanding selectivity in C-H activation reactions.

Chem. Eur. J. 2014, 20, No. 40, 12704-12718

Johannes Schranck, Anis Tlili, Matthias Beller
Functionalization of Remote C-H Bonds: Expanding the Frontier [Highlight]

Functionalization of Remote C-H Bonds: Expanding the Frontier

Novel tool set: New methodologies for the functionalization of remote C-H bonds have been developed recently. In diverse approaches high selectivities are achieved for the functionalization of less reactive C(sp2)-H as well as C(sp3)-H bonds distal to any substituents.

Angew. Chem. Int. Ed. 2014, 53, No. 36, 9426-9428

Frédéric Liron, Julie Oble, Mélanie M. Lorion, Giovanni Poli
Direct Allylic Functionalization Through Pd-Catalyzed C–H Activation [Microreview]

Direct Allylic Functionalization Through Pd-Catalyzed C–H Activation

This review outlines some selected examples and present challenges relating to palladium-catalyzed direct allylic functionalization. This old reaction, ignored for many years, is enjoying a new age.

Eur. J. Org. Chem. 2014, No. 27, 5863-5883

Laurent Djakovitch, François-Xavier Felpin
Direct C sp2-H and C sp3-H Arylation Enabled by Heterogeneous Palladium Catalysts [Minireview]

Direct C sp2-H and C sp3-H Arylation Enabled by Heterogeneous Palladium Catalysts

When palladium meets a support: The functionalization of the C-H bond is the most straightforward approach to create new bonds. Although most studies involve homogeneous transition-metal catalysts, in this Minireview we aim to give a picture of recent advances of direct C-H arylations enabled by heterogeneous Pd catalysts.

ChemCatChem 2014, 6, No. 08, 2175-2187

Jamal Koubachi, Saïd El Kazzouli, Mosto Bousmina, Gérald Guillaumet
Functionalization of Imidazo[1,2-a]pyridines by Means of Metal-Catalyzed Cross-Coupling Reactions [Microreview]

Functionalization of Imidazo[1,2-a]pyridines by Means of Metal-Catalyzed Cross-Coupling Reactions

The latest developments in the field of imidazo[1,2-a]pyridine functionalization by means of cross-coupling reactions such as the Sonogashira, Heck, Negishi, Suzuki–Miyaura, and Stille reactions, as well as by C-arylation, C-alkenylation, carbonylation, and double functionalization, are reviewed and discussed.

Eur. J. Org. Chem. 2014, No. 24, 5119-5138

Ligands Control Reactivity and Selectivity in Palladium-Catalyzed Functionalization of Unactivated C sp3-H Bonds

Ligands at the wheel: The pivotal role of ligands for the palladium-catalyzed functionalization of remote C sp3-H bonds has been demonstrated. The presence of the ligand enhances the reactivity of the inert C sp3-H bond and controls the selectivity of the process. DG=Directing group, FG=functional group.

ChemCatChem 2014, 6, No. 08, 2188-2190

Direct Functionalization with Complete and Switchable Positional Control: Free Phenol as a Role Model

PhenAll: Recent breakthroughs in site-selective and direct functionalization of free phenols by transition-metal-catalyzed C-O or C-H bond activation are highlighted here as role models for the complete and switchable positional control of transformations of important core structures.

Angew. Chem. Int. Ed. 2014, 53, No. 30, 7710-7712

Yan Li, Yun Wu, Guang-Shui Li, Xi-Sheng Wang
Palladium-Catalyzed C-F Bond Formation via Directed C-H Activation [Review]

Christoph Kornhaaß, Christian Kuper, Lutz Ackermann
Ferrocenylalkynes for Ruthenium-Catalyzed Isohypsic C-H/N-O Bond Functionalizations [Update]

Suman De Sarkar, Weiping Liu, Sergei I. Kozhushkov, Lutz Ackermann
Weakly Coordinating Directing Groups for Ruthenium(II)- Catalyzed C-H Activation [Review]

Zhao-Lei Yan, Wen-Liang Chen, Ya-Ru Gao, Shuai Mao, Yan-Lei Zhang, Yong-Qiang Wang
Palladium-Catalyzed Intermolecular C-2 Alkenylation of Indoles Using Oxygen as the Oxidant [Update]

José Luis García Ruano, José Alemán, Alejandro Parra, Leyre Marzo
Sulfonyl Acetylenes as Alkynylating Reagents Under Radical or Anionic Conditions [Microreview]

Sulfonyl Acetylenes as Alkynylating Reagents Under Radical or Anionic Conditions

We summarize a powerful methodology for the alkynylation of C(sp3), C(sp2), and C(sp) carbon atoms, as well as some heteroatoms, with alkynylsulfones. It is based on the fact that β-substituted sulfonylacetylenes undergo unexpected anti-Michael addition of organolithiums and radical species, giving intermediates that evolve into alkynyl derivatives in situ by elimination of the anion or radical TolSO2.

Eur. J. Org. Chem. 2014, No. 08, 1577-1588

Philipp J. Gritsch, Christian Leitner, Magnus Pfaffenbach, Tanja Gaich
The Witkop Cyclization: A Photoinduced C-H Activation of the Indole System [Minireview]

The Witkop Cyclization: A Photoinduced C-H Activation of the Indole System

To wit: The title reaction resembles a photoinduced electron-transfer process, and allows the direct formation of medium-sized lactams by C-H activation of the indole nucleus. Therefore it is a versatile tool for the construction of polycyclic indole alkaloid scaffolds.

Angew. Chem. Int. Ed. 2014, 53, No. 05, 1208-1217

Towards Ideal Synthesis: Alkenylation of Aryl C-H Bonds by a Fujiwara–Moritani Reaction

Chemical power tools: The Fujiwara–Moritani reaction is the palladium-catalyzed coupling reaction of a simple aryl C-H bond with an alkenyl C-H bond to form a new C-C bond (see scheme). This Minireview focuses on the advances in the past five years related to the activation of various aryl C-H bonds in this coupling reaction.

Chem. Eur. J. 2014, 20, No. 03, 634-642

The Cross-Dehydrogenative Coupling of Csp3-H Bonds: A Versatile Strategy for C-C Bond Formations

Waste not, want not: The title CDC reactions have emerged as versatile tools for selective and waste-minimized C-C bond formations. They rely on the direct coupling of two different C-H bonds under oxidative conditions. This Review focuses on the recent progress in cross-dehydrogenative Csp3-C formation and provides a comprehensive overview on existing procedures and employed methodologies.

Angew. Chem. Int. Ed. 2014, 53, No. 01, 74-100

Yinuo Wu, Jun Wang, Fei Mao, Fuk Yee Kwong
Palladium-Catalyzed Cross-Dehydrogenative Functionalization of C(sp2)-H Bonds [Focus Review]

Palladium-Catalyzed Cross-Dehydrogenative Functionalization of C(sp2)-H Bonds

Caught in the cross-fire: This Review highlights the recent developments in catalytic cross-dehydrogenative coupling (CDC) reactions, which join together two aromatic C-H fragments through a palladium-catalyzed dehydrogenative pathway.

Chem. Asian J. 2014, 9, No. 01, 26-47

New Site-Selective Organoradical Based on Hypervalent Iodine Reagent for Controlled Alkane sp3 C-H Oxidations

Large Iodine: The site-selective oxidation of unactivated secondary sp3 C-H bonds was accomplished by using a newly defined reactive hypervalent iodine(III) radical in the presence of tert-butyl hydroperoxide (see scheme). Recent studies on hypervalent iodine radicals have significantly contributed to the further development and design of organic molecules in radical oxidation chemistry.

ChemCatChem 2014, 6, No. 01, 76-78

© Wiley-VCH 2013.