Palladium-catalyzed carbonylative cyclization of alkene-tethered indoles with phenols or arylboronic acids:Construction of carbonyl-containing indolo[2,1-a]isoquinoline derivatives

A novel palladium-catalyzed carbonylative cyclization of alkene-tethered indoles with phenols or arylboronic acids is described,which provides a facile approach to access indolo[2,1-a]isoquinoline scaffolds.This method employs benzene-1,3,5-triyl triformate(TFBen)as the CO surrogate for the incorporation of a carbonyl group into indolo[2,1-a]isoquinoline scaffolds,and a variety of carbonyl-containing indolo[2,1-a]isoquinoline derivatives are prepared in good yields.

Nickel-Catalyzed Difluoromethylation of Arylboronic Acids with Bromodifluoromethane

Although bromodifluoromethane （BrCF2H） is a simple and readily available fluorine source, direct formation of difluoromethylated arenes with BrCF2H has not been reported. Herein, we describe an efficient method to access difluoromethylated arenes through a nickel-catalyzed difluoromethylation of arylboronic acids with BrCF2H. The reaction exhibits high efficiency, good functional group tolerance and broad substrate scope, thus providing an efficient route for applications in drug discovery and development. Preliminary mechanistic studies reveal that a difluoromethyl radical is involved in the reaction.

Silica-supported Copper（Ⅱ） Catalyzed Coupling of Arylboronic Acids with Imidazoles

Immobilized copper（Ⅱ） in organic-inorganic hybrid materials catalyzed Ar-N coupling of arylboronic acids with imidazoles has been developed. Arylboronic acids reacted with imidazoles smoothly in the presence of a 3-（2-aminoethylamino）propyl functionalized silica gel immobilized copper（Ⅱ） catalyst （10 mol%） in methanol without any additives and bases. The reactions generated the corresponding cross-coupling products in good yields. Furthermore, silica-supported copper can be recovered and recycled by a simple filtration procedure and used for five consecutive trials without decreases in activity.

Inhibition of Homo-coupling of Arylboronic Acids in Ligand Free Pd（ll）-Catalyzed Suzuki Reaction

A series of solvents were examined for the ligand free Pd（II）-catalyzed Suzuki reaction of 4-bromotoluene with phenylboronic acid. It was found that the PdCl2/i-PrOH system could efficiently inhibit the homo-coupling of phenylboronic acid and give a cross-coupling product in high yields. The substrates with a wide variety of functional groups were tolerated in the system. A possible mechanism for this system was proposed.

Metal-free synthesis of substituted phenols from arylboronic acids in water at room temperature

A convenient,efficient and practical metal-free method for the synthesis of substituted phenols from arylboronic acids has been developed.The protocol uses hydrogen peroxide as a hydroxylating agent ammonium bicarbonate as an additive,and the reactions were conveniently performed in water at room temperature.The method shows an excellent tolerance of functional groups,so it will find a wide variety of applications in academic and industrial research.

Rh(Ⅲ)-catalyzed C8 arylation of quinoline N-oxides with arylboronic acids

Herein,we report the first Rh~Ⅲ-catalyzed regioselective C8 arylation of quinoline N-oxides with commercially available arylboronic acids as coupling partners.This procedure is simple,and the reaction shows perfect regioselectivity,a broad substrate scope,and isolated yields of up to 92%.We demonstrate the utility of the reaction by using it for late-stage functionalization of a fungicide.

One-Pot Synthesis of Triarylmethanes via Metal-Free Reductive Coupling of Diaryl Ketones, Tosylhydrazide, and Arylboronic Acids

Synthesis of triarylmethanes via metal-free reductive coupling of diaryl ketone, tosylhydrazide, and arylboronic acids has been developed. This methodology is realized via one-pot two-step reactions involving the preparation of N-tosylhydrazones by reacting tosylhydrazide with diaryl ketone derivatives, followed by the reductive coupling with arylboronic acid in the presence of potassium carbonate to afford various triarylmethanes analogues in moder- ate to good yields. Importantly, the system presented here enables the use of easily accessible starting materials and a series of substrates with diverse functional group could be tolerant in this reaction. This approach could also be particularly useful for the synthesis of triaryl-substituted carbazolyl compounds.

Copper-catalyzed three-component reaction of imidazo[1,2-a]pyridine with elemental sulfur and arylboronic acid to produce sulfenylimidazo[1,2-a]pyridines

In this work, an efficient copper-catalyzed three-component reaction for the synthesis of sulfenylimidazo [1,2-a]pyridines using elemental sulfur as the sulfenylating agents has been developed. The reaction could proceed smoothly with a high degree of functional group tolerance and provide the desired products in moderate to good yield.

Direct Arylation of Substituted Pyridines with Arylboronic Acids Catalyzed by Iron(Ⅱ) Oxalate

The direct arylation of substituted pyridines with several arylboronic acids has been developed.This transformation could proceed readily at ambient temperature using inexpensive reagents:iron(Ⅱ)oxalate as a catalyst,potassium persulfate as a co-oxidant,which can afford the arylated products in mild to good yields.The mechanism is presumed to proceed through a nucleophilic radical addition to the pyridines with in situ reoxidation.

Green and controllable metal-free nitrification and nitration of arylboronic acids

A novel and green nitrating reagent has been developed for the nitrification and nitration of arylboronic acids, which can be controlled by the reaction conditions. The process provides an attractive alternative to the traditional nitration protocols.

Mn(Ⅲ)-mediated radical reaction of 2-isocyano-6-alkenyl(alkynyl)benzonitriles with arylboronic acids:Synthesis of pyrroloisoquinoline derivatives

A Mn(Ⅲ) mediated radical reaction of new designed multi-functionalized 2-isocyano-6-alkenyl(alkynyl)benzonitriles with arylboronic acids has been developed.This reaction provides a method for the synthesis of pyrroloisoquinoline derivatives through the formation of two C-C bonds and one C-N bond via radical cascade cyclization in one step.

KMnO4-mediated direct selective radical cross-coupling：An effective strategy for C2 arylation of quinoline N-oxide with arylboronic acids

Direct C—H functionalization of quinoline N-oxides with arylboronic acids is achieved using KMnOas the sole and efficient oxidative system.This method provides an efficient protocol to construct regioselectively 2-arylquinoline N-oxides via radical cross-coupling reaction in moderated to good yields under mild conditions.

Palladium Catalyzed Suzuki Cross-coupling Reaction in Molten Tetra-n-butylammonium Bromide

A practical procedure for palladium catalyzed Suzuki cross-coupling reaction of arylboronic acids with aryl hal-ides, including aryl chlorides in molten tetra-n-butylammonium bromide (TBAB) was developed. The reaction exhibits high efficiency and functional group tolerance. The recovery of the catalyst and molten n-Bu4NBr was also investigated.

Nickel-Catalyzed Direct Coupling of Allylic Alcohols with Organoboron Reagents

The direct coupling of allylic alcohols with arylboronic acids or their derivatives catalyzed by Ni（cod）2 in the presence of a catalytic amount of base has been developed. A wide variety of allylic substrates or aryIboronic acids turned out to be applicable to this catalytic system. The present method does not require the use of ligands for stabilizing the nickel catalyst in most cases or additional activators for activation of altylic alcohols.