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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]

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 report here "sandwich" diimine‐copper(I) catalysts for C(sp3)−H bond functionalization. Reactions of alkanes and ethers with trimethylsilyldiazomethane, ethyl diazoacetate, and trifluoromethyl‐diazomethane have been demonstrated. We also report C(sp3)−H bond methylation, benzylation, and diphenylmethylation by diazomethane, aryldiazomethanes, and diphenyldiazomethane. These reactions are rare examples of base‐metal catalyzed, intermolecular C(sp3)−H functionalizations by employing unactivated diazo compounds. Electrophilicity and unique steric environment of "sandwich"‐copper catalysts are likely reasons for their catalytic efficiency. [ABSTRACT FROM AUTHOR]

Four extensively fluorinated tetraphenylethylenes (TPE) and one extensively fluorinated triphenylethylene have been synthesized using combinations of copper‐catalyzed C−H functionalization reactions and Stille coupling reactions. Surprisingly, in contrast to the parent TPE, these compounds show little to no aggregation‐induced emission (AIE). Instead, photocyclization into fluorinated phenanthrene products occurs. Effects of solvent and oxygen on the yield and selectivity of this photocyclization have been examined. [ABSTRACT FROM AUTHOR]

A new class of chiral phosphines belonging to the P-aryl-2-phosphabicyclo octane family (PBO) is prepared by enantioselective synthesis starting from lactate esters and 2,2-dimethylcyclopentanone enolate. A substantial effort was invested to probe the relationship between catalyst purity and enantioselectivity.

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]

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]

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]

A method is developed for auxiliary-directed, palladium-catalyzed [beta]-arylation and alkylation of [sp.sup.3] and [sp.sup.2] C-H bonds in carboxylic acid derivatives. 8-Aminoquinoline auxiliary has produced the best results for alkylation of [sp.sup.3] and [sp.sup.2] C-H bonds, where functional group tolerance is observed and amino- and hydroxyl-acid derivatives are functionalized.

Microfluidics is used for implementing genetic algorithms (GA) for discovering new homogeneous catalysts by using the oxidation of methane by molecular oxygen as a model system. The Pt/Fe system has shown the compatibility of iron with the entire catalytic cycle and the approach of GA-guided evolution has the potential to accelerate the discovery in catalysis and other areas

A general method is developed for copper-catalyzed deprotonative dimerization of arenes by using oxygen as the terminal oxidant. The electron-rich and electron-poor heterocycles as well as electron-poor arenes are reactive and the method is tolerant to functionalities like nitro, cyano, dialkylamino and ester groups.

A general method is developed for in situ trapping of arylmetal intermediates by halogen, sulfur, ketone and aldehyde electrophiles, which has produced the functionalization of the most acidic position in arene. [K.sub.3]P[O.sub.4] base is used for functionalizing pentafluorobenzene, benzothiazole and benzoxazole.

A general method is developed for copper-catalyzed arylation of [sp.sup.2] C-H bonds with p[K.sub.a]'s below 35. Electron-poor arenes possessing at least two electron-withdrawing groups on a benzene ring is arylated and two arylcopper-phenanthroline complex intermediates are prepared independently.

The development a palladium-catalyzed benzamide sequence ortho-arylation/rection with [(C[F.sub.3]CO).sub.2]O for convenient one-pot synthesis of ortho-arylated benzonitriles and fluorenone derivatives is reported. The N-propyl benzamides is converted to fluorenones while N-cyclohexyl benzamides yield benzonitrile derivatives.

The article explains the development and efficiency of a new approach for direct arylation of heterocycle C-H bonds by aryl halides, using copper as a catalyst. The technique can be widely used for organic synthesis due to its readily available starting materials.

A study conducted demonstrates that anilides possessing a number of different acyl groups could be arylated by aryl iodides by using palladium catalysis. The arylation products could be converted to phenanthridines by the reaction with trifluoroacetic anhydride.

Two new palladium-catalyzed methods are developed for the direct ortho-arylation of free benzoic acids. Inter- and intramolecular isotope effects for the benzoic acid arylation by aryl chlorides are determined and are found to be the same with a magnitude of 4.4 pointing toward heterolytic C-H cleavage as the turnover-limiting step.

A strategy in which C-H activation reactions promoted by Pd(II) are combined with beta-heteroatom elimination to create a catalytic cycle and achieve the arylation of haloolefins is described. The catalytic cycle can be subdivided into four parts, which includes C-H activation.

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]

Creating stimuli-responsive materials with switchable solid-state luminescence remains a challenge. We report that the solvation of a novel organic fluorophore can be utilized to prepare such a material, which emits in the blue (442–446 nm) region when wet and in the green (497–503 nm) region when dry. [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]

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]

A general method is described for the copper-catalyzed arylation and alkenylation of polyfluorobenzene C-H bonds. The results are obtained by using a combination of copper iodide catalyst, phenanthroline ligand, aryl bromide or aryl iodide coupling partner, and DMF or DMF/xylene mixed solvent.

A new arylation process based on C-H is developed and it allows for the beta-arylation of carboxylic acid derivatives and gamma-arylation of amine derivatives. Efforts are underway to extend this methodology to arylation of esters and alkenylation of amides and esters.

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 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]