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A general method for ortho-functionalization of pentafluorosulfanyl arenes has been developed. ortho-Lithiation with lithium tetramethylpiperidide at −60 °C in the presence of silicon, germanium, and tin electrophiles affords trapped products in moderate to high yields. Precise temperature regimes and the presence of electrophiles during lithiation are important for successful reactions, since the pentafluorosulfanyl group acts as a competent leaving group at temperatures above −40 °C. Fluoro, bromo, iodo, enolizable keto, cyano, ester, amide, and unsubstituted amino functionalities are compatible with the reaction conditions. Conversion of 2-dimethylsilylpentafluorosulfanyl benzene to 2-halosubstituted derivatives, useful as starting materials in cross-coupling chemistry, was also demonstrated. [ABSTRACT FROM AUTHOR]

N-Iminopyridinium ylides are competent monodentate directing groups for cobalt-catalysed annulation of sp2 C–H bonds with internal alkynes. The pyridine moiety in the ylide serves as an internal oxidant and is cleaved during the reaction. The annulation reactions possess excellent compatibility with heterocyclic substrates, tolerating furan, thiophene, pyridine, pyrrole, pyrazole, and indole functionalities. [ABSTRACT FROM AUTHOR]

Polyfluorinated substituents often enhance effectiveness, improve the stability within metabolic processes, and boost the lipophilicity of biologically active compounds. However, methods for their introduction into aliphatic carbon chains remain very limited. A potentially general route to integrate the fluorinated scaffolds into organic molecules involves insertion of fluorine‐containing carbenes into C(sp3)−H bonds. The electron‐withdrawing characteristics of perfluoroalkyl groups enhances the reactivity of these carbenes which should enable the functionalization of unactivated C(sp3)−H bonds. Curiously, it appears that use of perfluoroalkyl‐containing carbenes in alkane C−H functionalization is exceedingly rare. This concept describes photolysis, enzymatic catalysis, and transition metal catalysis as three primary approaches to C(sp3)−H functionalization by trifluoromethylcarbene and its homologues. [ABSTRACT FROM AUTHOR]

A general method for synthesis of 1,2-bis-trifluoromethylthioarenes has been developed. Arynes generated from silyl aryl triflates or halides react with bis(trifluoromethyl)disulfide to afford 1,2-bis-trifluoromethylthioarenes. Aryl, alkyl, ester, halide, and methoxy functionalities are compatible with reaction conditions. Use of bis(perfluoroaryl)disulfides gave moderate yields of aryne disulfenylation or cyclization to fluorinated dibenzothiophenes. [ABSTRACT FROM AUTHOR]

Phosphine-iminophosphorane palladium complexes were synthesized and studied as catalysts for ethylene polymerization. The effect of the substituents on the phosphine and iminophosphorane moieties was investigated. Catalyst 15 promoted the conversion of ethylene to moderate molecular weight linear polyethylene ( M n ≈ 14000 g/mol, branches/1000C ≈ 7). This catalyst proved to be stable at temperatures up to 100 °C with a turnover frequency of 2100 h-1. [ABSTRACT FROM AUTHOR]

We report here "sandwich"‐diimine copper complex‐catalyzed trifluoroethylation and pentafluoropropylation of unactivated C(sp3)−H bonds in alkyl esters, halides, and protected amines by employing CF3CHN2 and CF3CF2CHN2 reagents. Reactions proceed in dichloromethane solvent at room temperature. Identical C−H functionalization conditions and stoichiometries are employed for generality and convenience. Selectivities for C−H insertions are higher for compounds possessing stronger electron‐withdrawing substituents. Preliminary mechanistic studies point to a mechanism involving a pre‐equilibrium forming a "sandwich"‐diimine copper‐CF3CHN2 complex followed by rate‐determining loss of nitrogen affording the reactive copper carbene. It reacts with trifluoromethyldiazomethane about 6.5 times faster than with 1‐fluoroadamantane explaining the need for slow addition of the diazo compound. [ABSTRACT FROM AUTHOR]

We have developed a method for palladium-catalyzed, pyrazole-directed sp3 C−H bond arylation by aryl iodides. The reaction employs a Pd(OAc)2 catalyst at 5-10 mol % loading and silver(I) oxide as a halide-removal agent, and it proceeds in acetic acid or acetic acid/hexafluoroisopropanol solvent. Ozonolysis of the pyrazole moiety affords pharmaceutically important β-phenethylamines. [ABSTRACT FROM AUTHOR]

We have developed a method for palladium-catalyzed, pyrazole-directed sp3 C−H bond arylation by aryl iodides. The reaction employs a Pd(OAc)2 catalyst at 5-10 mol % loading and silver(I) oxide as a halide-removal agent, and it proceeds in acetic acid or acetic acid/hexafluoroisopropanol solvent. Ozonolysis of the pyrazole moiety affords pharmaceutically important β-phenethylamines. [ABSTRACT FROM AUTHOR]

The palladium diphosphine complex 4 converts ethylene to hyperbranched unsaturated oligomers (Mn ≈ 330 g/mol) at 22 °C. In addition to the high stability of this catalyst observed at temperatures up to 75 °C, an increase of the reaction temperature leads to a decrease in branching densities of the oligomers, in sharp contrast to the palladium and nickel diimine catalyst systems. One-pot oligomerizations/hydrogenations were carried out to form hyperbranched saturated oligomers. [ABSTRACT FROM AUTHOR]

Silylaryl bromides and iodides can be prepared in one step from commercially available starting materials. Arynes can be generated from these compounds under conditions nearly identical to those employed for silylaryl triflates. Three distinct transformations, ortho-arylation of N-tritylanilines, intermolecular addition of arynes to amides, and reaction of ureas with arynes, were shown to be successful for the new aryne precursors. The main advantage of silylaryl halides relative to silyl aryl triflates is their one-step preparation from commercially available starting materials. [ABSTRACT FROM AUTHOR]

An operationally simple and general method for copper-catalyzed, aminoquinoline-assisted amination of βC(sp2)-H bonds of benzoic acid derivatives is reported. The reaction employs Cu(OAc)2 or (Cu0H)2C03 catalysts, an amine coupling partner, and oxygen from air as a terminal oxidant. Exceptionally high generality with respect to amine coupling partners is observed. Specifically, primary and secondary aliphatic and aromatic amines, heterocycles, such as indoles, pyrazole, and carbazole, sulfonamides, as well as electron-deficient aromatic and heteroaromatic amines are competent coupling components. [ABSTRACT FROM AUTHOR]

Conspectus: In recent years, carbon-hydrogen bond functionalization has evolved from an organometallic curiosity to a tool used in mainstream applications in the synthesis of complex natural products and drugs. The use of C-H bonds as a transformable functional group is advantageous because these bonds are the most abundant functionality in organic molecules. One-step conversion of these bonds to the desired functionality shortens synthetic pathways, saving reagents, solvents, and labor. Less chemical waste is generated as well, showing that this chemistry is environmentally beneficial. This Account describes the development and use of bidentate, monoanionic auxiliaries for transition-metal-catalyzed C-H bond functionalization reactions. The chemistry was initially developed to overcome the limitations with palladium-catalyzed C-H bond functionalization assisted by monodentate directing groups. By the use of electron-rich bidentate directing groups, functionalization of unactivated sp³ C-H bonds under palladium catalysis has been developed. Furthermore, a number of abundant base-metal complexes catalyze functionalization of sp² C-H bonds. At this point, aminoquinoline, picolinic acid, and related compounds are among the most used and versatile directing moieties in C-H bond functionalization chemistry. These groups facilitate catalytic functionalization of sp² and sp³ C-H bonds by iron, cobalt, nickel, copper, ruthenium, rhodium, and palladium complexes. Exceptionally general reactivity is observed, enabling, among other transformations, direct arylation, alkylation, fluorination, sulfenylation, amination, etherification, carbonylation, and alkenylation of carbon-hydrogen bonds. The versatility of these auxilaries can be attributed to the following factors. First, they are capable of stabilizing high oxidation states of transition metals, thereby facilitating the C-H bond functionalization step. Second, the directing groups can be removed, enabling their use in synthesis and functionalization of natural products and medicinally relevant substances. While the development of these directing groups presents a significant advance, several limitations of this methodology are apparent. The use of expensive second-row transition metal catalysts is still required for efficient sp³ C-H bond functionalization. Furthermore, the need to install and subsequently remove the relatively expensive directing group is a disadvantage. [ABSTRACT FROM AUTHOR]

A method for aminoquinoline-directed, cobalt-promoted dimerization of benzamides has been developed. Reactions proceed in ethanol solvent in the presence of Mn(OAc)2 cocatalyst and Na2CO3 base and use oxygen as a terminal oxidant. Bromo, iodo, nitro, ether, and ester moieties are compatible with the reaction conditions. Cross-coupling of electronically dissimilar aminoquinoline benzamides proceeds with modest yields and selectivities. [ABSTRACT FROM AUTHOR]

A method for cobalt-catalyzed, aminoquinoline- and picolinamide-directed C(sp2)H bond alkenylation by alkynes was developed. The method shows excellent functional-group tolerance and both internal and terminal alkynes are competent substrates for the coupling. The reaction employs a Co(OAc)2⋅4 H2O catalyst, Mn(OAc)2 co-catalyst, and oxygen (from air) as a terminal oxidant. [ABSTRACT FROM AUTHOR]

A method for cobalt-catalyzed, aminoquinoline- and picolinamide-directed C(sp2)H bond alkenylation by alkynes was developed. The method shows excellent functional-group tolerance and both internal and terminal alkynes are competent substrates for the coupling. The reaction employs a Co(OAc)2⋅4 H2O catalyst, Mn(OAc)2 co-catalyst, and oxygen (from air) as a terminal oxidant. [ABSTRACT FROM AUTHOR]

A methodfor cobalt-catalyzed, aminoquinoline-directed ortho-functionalization of sp2C–H bondswith alkenes has been developed. Reactions proceed at room temperaturein trifluoroethanol solvent, use oxygen from air as an oxidant, andrequire Mn(OAc)3as a cocatalyst. Benzoic, heteroaromatic,and acrylic acid aminoquinoline amides react with ethylene as wellas mono- and disubstituted alkenes affording products in good yields.Excellent functional group tolerance is observed; halogen, nitro,ether, and unprotected alcohol functionalities are compatible withthe reaction conditions. [ABSTRACT FROM AUTHOR]

Aminoquinoline-directed, palladium-catalyzed sp3 C–H bond arylation in phosphonamidates and phosphinic amides is reported. The reaction employs Pd(OAc)2 as a catalyst at 10 mol% loading and cesium phosphate or potassium carbonate as a base in 1,2-dichlorobenzene as a solvent. The directing group can be removed under basic conditions to afford phosphonic acid esters. The chemistry described here is the first example of unactivated sp3 C–H bond arylation by using a phosphorus-containing directing group. [ABSTRACT FROM AUTHOR]

A method for direct, auxiliary-assisted alkoxylation and phenoxylation of β-sp2C–H bonds of benzoic acid derivatives and γ-sp2C–H bonds of amine derivatives is reported. The reaction employs (CuOH)2CO3catalyst, air as an oxidant, phenol or alcohol coupling partner, DMF, pyridine, or DMPU solvent, and K2CO3, tetramethylguanidine, or K3PO4base at 70–130 °C. [ABSTRACT FROM AUTHOR]

A method for direct, transition-metal-free ortho-arylation of anilines by aryl chlorides, bromides, fluorides, and triflates has been developed. This methodology provides the most direct approach to 2-arylanilines since no protecting or directing groups on nitrogen are required. The arylation is functional-group tolerant, with alkene, ether, trifluoromethyl, dimethylamino, carbonyl, chloro, and cyano functionalities tolerated. Phenylation of enantiopure binaphthyldiamine affords a product with >99% ee. [ABSTRACT FROM AUTHOR]

A method for five- and six-membered heterocycle formation by palladium-catalyzed C-H/N-H coupling is presented. The method employs a picolinamide directing group, PhI(OAc)2 oxidant, and toluene solvent at 80-120 °C. Cyclization is effective for sp² as well as aliphatic and benzylic sp³ C-H bonds. [ABSTRACT FROM AUTHOR]

We have developed a method for auxiliary-directed, palladium-catalyzed β-arylation and alkylation of sp³ and sp² C-H bonds in carboxylic acid derivatives. The method employs a carboxylic acid 2-methylthioaniline- or 8-aminoquinoline amide substrate, aryl or alkyl iodide coupling partner, palladium acetate catalyst, and an inorganic base. By employing 2-methylthioaniline auxiliary, selective monoarylation of primary sp³ C-H bonds can be achieved. If arylation of secondary sp³ C-H bonds is desired, 8-aminoquinoline auxiliary may be used. For alkylation of sp³ and sp² C-H bonds, 8-aminoquinoline auxiliary affords the best results. Some functional group tolerance is observed and amino- and hydroxy-acid derivatives can be functionalized. Preliminary mechanistic studies have been performed. A palladacycle intermediate has been isolated, characterized by X-ray crystallography, and its reactions have been studied. [ABSTRACT FROM AUTHOR]

The palladium-catalyzed direct arylation of anilides possessing several N-acyl substituents has been demonstrated. Removal of the acyl group by base hydrolysis allows a short and efficient synthesis of 2-aryl or 2,6-diarylanilines. The method is functional group tolerant and allows the presence of chloride and bromide substituents on both the anilide and aryl iodide coupling components. The arylation products can be converted to phenanthridines by the reaction with trifluoroacetic anhydride. [ABSTRACT FROM AUTHOR]

A new class of chiral phosphines belonging to the P-aryl-2-phosphabicyclo[3.3.0]octane family (PBO) has been prepared by enantioselective synthesis starting from lactate esters and 2,2-dimethylcyclopentanone enolate 5. A selective enolate alkylation method has been developed for preparation of 9 and 10 using a chelating ester substituent in the triflate alkylating agent 11. Subsequent conversion to the PBO catalysts 2 and 39 relies on a diastereoselective cyclization from the cyclic sulfate 17 and LiPHAr to afford the more hindered endo-aryl phosphines. These phosphines function as efficient catalysts for the kinetic resolutions of aryl alkyl carbinols by benzoylation (16, 21, 22) or iso-butyroylation in the case of the less hindered aryl alkyl carbinol substrates. With o-substituted aryl alkyl carbinols, the enantioselectivities exceed 100, and s = 380 ± 10 has been demonstrated in the case of methyl mesityl carbinol. The PBOcatalyzed acylations probably involve a P-acylphosphonium carboxylate intermediate and a tightly ion paired transition state. [ABSTRACT FROM AUTHOR]

A method for direct carbonylationof aminoquinoline benzamideshas been developed. Reactions proceed at room temperature in trifluoroethanolsolvent, use oxygen from air as an oxidant, and require Mn(OAc)3as a cocatalyst. Benzoic and acrylic acid derivatives canbe carbonylated by carbon monoxide affording imides in good yields.Halogen, nitro, ether, cyano, and ester functional groups are tolerated.The directing group can be removed under mild conditions affordingphthalimides. [ABSTRACT FROM AUTHOR]

A transition-metal-free method for arylation of heterocycle and arene carbon-hydrogen bonds by aryl chlorides and fluorides has been developed. The reactions proceed via aryne intermediates and are highly regioselective with respect to the C-H bond coupling component. [ABSTRACT FROM AUTHOR]

The reactivity of NiII and PdII olefin polymerization catalysts can be enhanced by introduction of electron‐withdrawing substituents on the supporting ligands rendering the metal centers more electrophilic. Reported here is a comparison of ethylene polymerization activity of a classical salicyliminato nickel catalyst substituted with the powerful electron‐withdrawing 2,4,6‐triphenylpyridinium (trippy) group to the ‐CF3 analogue. The trippy substituent is substantially more electron‐withdrawing (σmeta=0.63) than the trifluoromethyl group (σmeta=0.43) which results in a ca. 8‐fold increase in catalytic turnover frequency. An additional advantage of trippy is the high steric bulk relative to the trifluoromethyl group. This feature results in a four‐fold increase in polymer molecular weight owing to enhanced retardation of chain transfer. A significant increase in catalyst lifetime is observed as well. [ABSTRACT FROM AUTHOR]

The reactivity of NiII and PdII olefin polymerization catalysts can be enhanced by introduction of electron‐withdrawing substituents on the supporting ligands rendering the metal centers more electrophilic. Reported here is a comparison of ethylene polymerization activity of a classical salicyliminato nickel catalyst substituted with the powerful electron‐withdrawing 2,4,6‐triphenylpyridinium (trippy) group to the ‐CF3 analogue. The trippy substituent is substantially more electron‐withdrawing (σmeta=0.63) than the trifluoromethyl group (σmeta=0.43) which results in a ca. 8‐fold increase in catalytic turnover frequency. An additional advantage of trippy is the high steric bulk relative to the trifluoromethyl group. This feature results in a four‐fold increase in polymer molecular weight owing to enhanced retardation of chain transfer. A significant increase in catalyst lifetime is observed as well. [ABSTRACT FROM AUTHOR]

Lithium 1,1-diadamantylamide (LDAM) base-promoted insertion of arynes into disulfide S–S bonds is described. After generation of arynes from readily available aryl halides and triflates, reactions with diaryl and diisopropyl disulfides afford the insertion products in moderate to excellent yields. Use of 1-cyclohexenyl triflate gave an excellent yield of 1,2-bis(phenylthio)cyclohexene. [ABSTRACT FROM AUTHOR]

Review: 169 refs. [ABSTRACT FROM AUTHOR]

Primary, secondary, and aromatic amines, heterocycles as well as electron-deficient aromatic and heteroaromatic are employed as amine coupling partners using Cu(OAc)2 or CuCO3·Cu(OH)2 as catalysts and oxygen from the air as the terminal oxidant. [ABSTRACT FROM AUTHOR]

The article discusses the method for copper-catalyzed, deprotonative dimerization of arenes by employing oxygen as the terminal oxidant. It states that copper is one of the first transition metals shown to promote functionalization of C-H bonds. It demonstrates that acidic C-H bonds can be arylated by aryl halides under copper analysis. It notes that such a method is tolerant to functionalities such as nitro, cyano, and amino.

The article presents a study that develops an efficient, copper-catalyzed method for the arylation, alkenylation and benzylation of polyfluoroarenes. Base on the experiment, the author found that arenes containing two or more fluorine substituents on the aromatic ring can be efficiently functionalized. It is claimed that the best results are obtained through a combination of copper iodide catalyst, phenanthroline ligand and aryl iodide coupling partner.

The article examines the effect of copper salts on the regioselectivity of palladium-catalyzed electron-rich heterocycle arylation. The said effect may arise from the involvement of organocopper intermediates in the reaction and this presumed intermediate can generate without a palladium cocatalyst that will become a cheap and efficient method for heterocycle arylation. Moreover, the best results were obtained by using a combination of lithium t-butoxide base aryl iodide coupling partner.

The article focuses on catalytic coupling of haloolefins with anilides. Extensive synthetic methodology has been developed based on oxidative addition reactions of C-X bonds (X = halogen, hetero-atom). Catalytic C-C bond-forming reactions arising from C-H bond activations are less common despite the wider availability, price, and environmental advantages of the starting hydrocarbons compared to functionalized compounds. The focus of many recent studies has moved from investigations of the C-H bond activation step to the application of these findings in catalytic processes. An example illustrating the catalytic C-C bond-forming reaction is palladium-catalyzed oxidative coupling of benzene derivatives with alkenes bearing electron-withdrawing groups.

An abstract of the article "Cobalt-Promoted Dimerization of Aminoquinoline Benzamides" by Liene Grigorjeva and Olafs Daugulis is presented.

Review: 75 refs. [ABSTRACT FROM AUTHOR]

The optimized procedure comprises air-oxygen as terminal oxidant and Mn(O-Ac)2 as co-catalyst to produce isoquinoline scaffolds which are of interest in pharmaceutical and natural product syntheses. [ABSTRACT FROM AUTHOR]

The coupling of N-(8-quinolinyl) substituted amides with olefins is developed using air as the oxidant. [ABSTRACT FROM AUTHOR]

A method for the cobalt catalyzed carbonylation of N-(8-quinolyl) substituted benzamides and acrylamides is developed using air as the oxidant in the presence of Mn(OAc)3 as promoter. [ABSTRACT FROM AUTHOR]

3,5-Dimethylpyrazole was employed as a monodentate directing group for palladium-catalyzed ortho-sp2 C-H arylation with aryl iodides. The reaction shows good functional group tolerance and outstanding selectivity for mono-ortho-arylation. Ozonolysis of ortho-arylated arylpyrazoles gave acylated biphenylamines that were further arylated to afford unsymmetrically substituted 2,6-diarylacetanilides. [ABSTRACT FROM AUTHOR]

Abstract: A method for cobalt‐catalyzed, carboxylate‐directed functionalization of arene C−H bonds is reported. Alkynes, styrenes, and 1,3‐dienes can be coupled with benzoic acids to provide cyclic products in good yields. The reactions proceed in the presence of a cobalt(II) hexafluoroacetylacetonate catalyst, (TMS)2NH base, Ce(SO4)2 cooxidant, and oxygen oxidant. [ABSTRACT FROM AUTHOR]

Abstract: A method for cobalt‐catalyzed, carboxylate‐directed functionalization of arene C−H bonds is reported. Alkynes, styrenes, and 1,3‐dienes can be coupled with benzoic acids to provide cyclic products in good yields. The reactions proceed in the presence of a cobalt(II) hexafluoroacetylacetonate catalyst, (TMS)2NH base, Ce(SO4)2 cooxidant, and oxygen oxidant. [ABSTRACT FROM AUTHOR]

Copolymerizations of ethylene with vinyltrialkoxysilanes using cationic (α-diimine)Ni(Me)(CH3CN)+ complexes 4a,b/B(C6F5)3 yield high molecular weight copolymers exhibiting highly branched to nearly linear backbones depending on reaction conditions and catalyst choice. Polymerizations are first-order in ethylene pressure and inverse-order in silane concentration. Microstructural analysis of the copolymers reveals both in-chain and chain-end incorporation of -Si(OR)3 groups whose ratios depend on temperature and ethylene pressure. Detailed low-temperature NMR spectroscopic investigations show that well-defined complex 3b (α-diimine)Ni(Me)(OEt2)+ reacts rapidly at -60 °C with vinyltrialkoxysilanes via both 2,1 and 1,2 insertion pathways to yield 4- and 5-membered chelates, respectively. Such chelates are the major catalyst resting states but are in rapid equilibrium with ethylene-opened chelates, (α-diimine)Ni(R)-(C2H4)+ complexes, the species responsible for chain growth. Chelate rearrangement via β-silyl elimination accounts for formation of chain-end -Si(OR)3 groups and constitutes a chain-transfer mechanism. Chelate formation and coordination of the Ni center to the ether moiety, R-O-Si, of the vinylsilane somewhat decreases the turnover frequency (TOF) relative to ethylene homopolymerization, but still remarkably high TOFs of up to 4.5 x 105 h-1 and overall productivities can be achieved. Activation of readily available (α-diimine)NiBr2 complexes 2 with a combination of AlMe3/B(C6F5)3/ [Ph3C][B(C6F5)4] yields a highly active and productive catalyst system for the convenient synthesis of the copolymer, a cross-linkable PE. For example, copolymers containing 0.23 mol % silane can be generated at 60 °C, 600 psig ethylene over 4 h with a productivity of 560 kg copolymer/g Ni. This method offers an alternative route to these materials, normally prepared via radical routes, which are precursors to the commercial cross-linked polyethylene, PEX-b. [ABSTRACT FROM AUTHOR]

We report a method for palladium-catalysed chain-running isomerization of terminal and internal alkenes. Using an air-stable 2,9-dimethylphenanthroline-palladium catalyst in combination with NaBAr4 promoter, olefins are converted to the most stable double bond isomer at −30 to 20 °C. Silyl enol ethers are readily formed from silylated allylic alcohols. Fluorinated substituents are compatible with the reaction conditions, allowing the synthesis of fluoroenolates. Catalyst loading as low as 0.05% can be employed on a gram scale. [ABSTRACT FROM AUTHOR]

Investigates the use of dual activation method for the esterification of hindered alcohols with anhydrides. Discussion on tertiary amines; Mechanistic interpretation of data; Anhydride-alcohol reactions.

The article presents chemical equations for article "Copper-Catalyzed Etherification of Arene C?H Bonds" by J. Roane and colleagues, published in "Organic Letters" in 2013 issue.

The deployment of different bases determines the reaction pathway: either formation of helicenes or ortho-arylation of phenols. [ABSTRACT FROM AUTHOR]

The present arylation of anilines proceeds selectively at the ortho-position. [ABSTRACT FROM AUTHOR]