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1,10-Phenanthroline-assisted, Ni(ii)-catalyzed para-carboxylation of phenol derivatives is reported.

With pyrimidine as the directing group, we achieved the meta-selective difluoromethylation of phenol derivatives using ruthenium as a catalyst. This synthetic scheme provided an efficient method for the syntheses of fluorine-containing phenol derivatives. A wide variety of phenol derivatives were well-suited, affording the corresponding products in moderate-to-good yields.

It has always been a challenge in free radical chemistry to control site selectivity during the reaction of free radicals with aromatic rings. Herein, we report the site-selective carboxylation of anisoles through the direct reaction of the bromoform radical with a benzene ring at the

Palladium-catalyzed non-directed C-H functionalization provides an efficient approach for direct functionalization of arenes, but it usually suffers from poor site selectivity, limiting its wide application. Herein, it is reported for the first time that the proton shuttle of 3,5-dimethyladamantane-1-carboxylic acid (1-DMAdCO2H) can affect the site selectivity during the C-H activation step in palladium-catalyzed non-directed C-H functionalization, leading to highly para-selective C-H olefination of TIPS-protected phenols. This transformation displayed good generality in realizing various other para-selective C-H functionalization reactions such as hydroxylation, halogenation, and allylation reactions. A wide variety of phenol derivatives including bioactive molecules of triclosan, thymol, and propofol, were compatible substrates, leading to the corresponding para-selective products in moderate to good yields. A preliminary mechanism study revealed that the spatial repulsion factor between proton shuttle and bulky protecting group resulted in the selective C-H activation at the less sterically hindered para-position. This new model non-directed para-selective C-H functionalization can provide a straightforward route for remote site-selective C-H activations.

Highly efficient, palladium-catalyzed, para-selective difluoromethylation of arene esters has been developed using [1,1'-biphenyl]-2-dicyclohexylphosphine as the effective ligand. A wide variety of arene esters bearing various functional groups were all compatible with the reaction conditions, leading to para-difluoromethylated products in moderate to good yields. Moreover, benzoylamide and benzenesulfonamide were also well-tolerated, suggesting that this novel catalyst system has broad applications to a variety of substrates.

A highly efficient silver-catalyzed dibenzylation of acetanilides by employing the benzhydrol derivatives as the coupling partners to yield triphenylmethane derivatives has been developed. Various functional groups were tolerated, leading to the corresponding products in moderate to good yields. Preliminary experimental results indicated that the silver ions activate the arene rings and the strong acid TfOH provides the carbocations.

The selective arylation of unactivated β or challenging γ primary and secondary β-C(sp3)–H bonds has been developed with a Cp*Rh(III) catalyst assisted by a trimethylpyrazole group. A rarely reported six-membered rhodacycle has been identified in rhodium-catalyzed C(sp3)–H activation reactions. Preliminary mechanistic studies have revealed that a concerted metalation–deprotonation pathway might be involved in the C–H activation step.

A practical and highly para-selective C-H difluoromethylation of aromatic ketones has been developed by employing tetrakis(triphenylphosphine)palladium(0) as the catalyst and triphenylphosphine as the ligand. In addition to general aromatic ketones, this transformation was compatible with bioactive compounds and well-known drugs, such as oxybenzone, ketoprofen, zaltoprofen, and propafenone. Moreover, a mechanistic study revealed that a palladium intermediate coordinated by a carbonyl group promotes highly para-selective difluoromethylation.

A highly efficient rhodium(III)-catalyzed direct oxidative annulation of acrylic acid with alkynes to form α-pyrones was developed. Various substituted acrylic acids were compatible in this transformation, affording the corresponding products in moderate to excellent yields under mild conditions.

Metal phthalocyanine (MPc) complexes can accelerate the catalytic oxidation of phenol and chlorophenol pollutants and therefore attract great attention. Although many efforts have been made on improving the catalytic performance of MPc, most of them are difficult to be recycled and cause secondary pollution. In this work, for the first time we report a novel biomimetic phthalocyanine catalyst of Fe3O4@Carbon@Tetranitro copper phthalocyanine (Fe3O4@C@TNCuPc) could catalyze the chromogenic identification of phenol and chlorophenol compounds in the presence of 4-aminoantipyrine and BuOOH without light irradiation or heating. Significantly, the Fe3O4@C@TNCuPc catalyst could be magnetically recycled and show high activity after four successive cycles of catalysis. On the basis of the electron paramagnetic resonance (EPR) test and active species trapping experiments, we propose that the oxidation of substrates was mediated by TNPcCuIII O active species generated from the homolytic cleavage of the O O bond in TNPcCuII OOBu.

The selective arylation of unactivated β or challenging γ primary and secondary β-C(sp