Enhanced catalytic degradation process of o-nitrochlorobenzene by palladium-catalyzed Fe^0 particles

Over Pd/Fe bimetallic catalyst, o-nitrochlorobenzene（o-NCB）, at a concentration of 20 mg/L in aqueous solutions, is rapidly converted to o-chloroaniline（o-CAN） first, and then quickly dechlorinated to aniline（AN） and Cl^- , without other intermediate reaction products. The aminated and dechlorinated reactions are believed to take place on the surface site of the Pd/Fe. The o-NCB removal efficiency and the next dechlorination rate increase with an increase of bulk loading of palladium and catalysts addition due to the increase of both the surface loading of palladium and the total surface area. These results indicate that reduction, amination and dechlorination of o- NCB by palladium-catalyzed Fe^0 particles, can be designed for remediation of contaminated groundwater.

Polyethylene Glycol as Support and Phase Transfer Catalyst in Aqueous Palladium-catalyzed Liquid-phase Synthesis

Excellent yields and purity were obtained in the aqueous medium Suzuki, Sonogashira, Stille and Heck reactions using palladium (II) as catalyst in liquid phase synthesis. Polyethylene glycol (PEG) acted as soluble polymeric support and phase transfer catalyst as well.

PALLADIUM-CATALYZED ARYLATION OF α-CYANOSULFONES UNDER PHASE TRANSFER CONDITIONS

(?)-Aryl-(?)-cyanosulfones are prepared under mild conditions with good yields by using palladium-catalyzed coupling reaction between aryl halides and (?)-cyanosulfones in the presence of phase transfer catalyst.

Palladium-Catalyzed Tandem Cyclization Strategy for the Assembly of 3-Halo-1,2,5-triarylpyrroles from N-Alkylanilines and Haloalkynes

This report discloses a distinctive palladium-catalyzed sequential tandem cyclization reaction of two molecular haloalkynes and one molecular N-alkylanilines,leading to the efficient assembly of various 3-halo-1,2,5-triarylpyrrole derivatives.Two carbon-carbon tri-ple bonds and one carbon-halogen bond in two molecular haloalkynes are transformed conveniently in one single step,which may involve the aminoalkynylation of haloalkyne and cyclization of the newly formed enyne intermediate.The high chemo-and regiose-lectivities,good functional group tolerance and late-stage modification of the halopyrrole products further illustrate the synthetic value of this strategy.

Palladium-catalyzed 3,4-hydroaminocarbonylation of conjugated dienes for formation ofβ,γ-unsaturated amides

Hydrocarbonylation of conjugated dienes is one of the most promising yet challenging methods for the synthesis of carbonyl compounds.Herein,we reported the development of an unprecedented palladium-catalyzed branched selective 3,4-hydroaminocarbonylation of 1,3-dienes with CO and amines hydrochloride to affordβ,γ-unsaturated amides.This reaction employs readily available starting materials(including anilines,amines,amino acids,peptides,aryl-1,3-dienes,alyl-1,3-dienes)and tolerates a wide range of functional groups,thus providing a facile and effective approach to access a diverse array ofα-substitutedβ,γ-unsaturated amides.Mechanistic investigations suggested that the hydropalladation of dienes is irreversible,and the insertion of CO into the allyl-Pd species is probably the rate-limiting step.

Arylhydrazones Derivatives Containing a Benzothiazole Moiety, Efficient Ligands in the Palladium-Catalyzed Mizoroki-Heck and Suzuki-Miyaura Cross-coupling Reactions under IR Irradiation

A simple arylhydrazone containing the benzothiazole moiety which may be used as an efficient ligand in the palladium-catalyzed Mizoroki-Heck and Suzuki-Miyaura cross-coupling reactions, under infrared irradiation as an alternative source of energy, is presented. The reactions proceeded with extremely high efficiency under mild conditions and produced very good yields.

Electrochemical Palladium-Catalyzed Intramolecular C-H Amination of 2-Amidobiaryls for Synthesis of Carbazoles

The synthesis of carbazoles based on the electrochemical Pd-catalyzed intramolecular C-H amination of 2-amidobiaryls through oxidative cross coupling has been achieved under mild reaction conditions.The reaction can be carried out in undivided cell without the addition of external chemical oxidant.Besides good functional group compatibility,the desired carbazoles can be scaled up and modified easily.Compared with previous methods,this protocol affords a simple and sustainable avenue for the construction of car-bazoles.

Palladium-catalyzed synthesis of 1,2,3,4-tetraalkyl-1,4-diarylbutadienes by cross-coupling of zirconacyclopentadienes with aryl iodides

A novel method for the synthesis of 1,2,3,4-tetraalkyl-1,4-diarylbutadienes was developed via palladiumcatalyzed cross-coupling of zirconacyclopentadienes with aryl iodides. Equivalent of Cu Cl was introduced to promote the reaction. The desired products were obtained in good to excellent yields and several of them were reported for the first time.

Palladium-Catalyzed Intermolecular Oxidative Diazidation of Alkenes

A palladium-catalyzed oxidative vicinal diazidation of alkenes has been developed, in which TMSN3 was used as azide source. Both styrenes and unactivated alkenes are suitable for this reaction. And trans-alkyldiazides were obtained as major products from cyclic alkenes with moderate to good diastereoselectivities. This reaction afforded an efficient way for the synthesis of useful 1,2-diamines after hydrogenation.

Divergent Syntheses of Pyridoacridine Alkaloids via Palladium-Catalyzed Reductive Cyclization with Nitro-Biarenes

Main observation and conclusion A divergent and novel protocol for the preparation of both pyrido[2,3,4-kl]acridine and pyrido[4,3,2-kl]acridine alkaloids was developed.This method featured the remote palladium-catalyzed reductive cyclization with Mo(CO)_(6) as reductant.A wide range of substrates including three types of nitro arenes were tolerated and afforded corresponding products in good to excellent yields.

Palladium-catalyzed oxidative cyclopropanation of enamides and norbornenes initiated by C–H activation

A novel palladium-catalyzed oxidative cyclopropanation of enamides and norbornenes has been developed. The reaction proceeded through palladium-catalyzed vinyl C–H bond activation of enamides followed by two migratory insertions, β-(N)H elimination and hydrolyzation cascade steps. The reaction tolerates a range of functional groups and provides an effective method for the synthesis of cyclopropane-fused norbornanes in good yields under mild conditions.

Palladium-Catalyzed Asymmetric Domino Heck/Carbocyclization/Suzuki Reaction:A Dearomatization of Nonactivated Naphthalenes

Herein,we report a novel palladium(Pd)-catalyzed asymmetric domino Heck/carbocyclization/Suzuki reaction of N-(2-bromoaryl)-2-naphthylacrylamides.The reaction involves a novel and enantioselective dearomative 1,2-insertion of the naphthalene group,thus providing a unique dearomatization strategy of nonactivated naphthalenes.A new phosphoramidite ligand L12,which displayed excellent reactivity and enantioselectivity in the reaction,has been developed.

Palladium-Catalyzed Three-Component Coupling Reaction of Allyl Carboxylates, Norbornenes and Diboronates InvoIving Sequential Olefins Insertion and Borylation Reaction

Summary of main observation and conclusion An efficient Pd-catalyzed three-component coupling reaction of allyl carboxylates, norbornenes and diboronates is described, which allows efficient assembly of C(sp3)-C(sp3) and C(sp3)-B bonds in a single process. Moreover, this approach shows advantages of good chemo- and regioselectivity, as well as good substrates suitability.

Palladium-catalyzed cascade synthesis of spirocyclic oxindoles via regioselective C2-H arylation and C8-H alkylation of naphthalene ring

A simultaneous C2-H arylation and C8-H alkylation of naphthalene ring has been achieved by palladiumcatalyzed cascade reaction of N-(2-halophenyl)-2-(naphthalen-1-yl)acrylamides with aryl iodides,which provides an efficient method for synthesizing various aryl-substituted spirocyclic oxindoles.The protocol enables three C-C bonds formation via an intramolecular Heck reaction and sequentially regioselective C-H bond activation.

Protecting-Group-Free One-Step Palladium-Catalyzed Coupling on C25 of Cucurbitacin B Expands Chemical Diversity with Improved Cytotoxicity against A549 Cells

The natural product cucurbitacin B has been widely studied because of its multiple biological activities,especially its potent antitumor effects.However,modifications of cucurbitacin B are mainly focused on the C2 and C16 site,studies on the C25 acetoxy group are still limited.We successfully developed a palladium-catalyzed allylic coupling of cucurbitacin B with boronic acids,providing a one-step approach to expand the chemical diversity of the C25 position.Our method was protecting-group-free,showing a good functional group tolerance and a wide substrate scope under mild reaction conditions.A library of 29 derivatives was prepared,compounds 2q and 2u showed higher cytotoxicity against A549 cells than cucurbitacin B,compounds 2n and 2o maintained potency,and the introduced hydroxyl and amino groups could be further derived.

Palladium-catalyzed oxidative homocoupling of 2-arylquinazolinones

Pd-catalyzed oxidative homocoupling of 2-arylquinazolinones was successfully developed for the direct construction of biaryls via C—H bond activation.New well-defined structure that possessed two quinazolinone units was obtained with high efficiency and atomic economy.The protocols offer an efficient approach to the synthetically useful and functionalized biaryls in good yields using quinazolinone as a directing group.

Site-Selective Palladium-Catalyzed 1,1-Arylamination of Terminal Alkenes

Many of the commonly used pharmaceuticals and biologically active natural products are nitrogencontaining compounds.Recently,the transitionmetal-catalyzed or the radical-mediated 1,2-carboamination of alkenes has been well explored to access amine scaffolds.However,synthetic strategies toward the 1,1-carboamination of alkenes are severely limited.Herein,we describe a method to achieve the 1,1-arylamination using readily available building blocks enabled by palladium catalysis.This sequential three step-Heck arylation,metal migration,followed by aza-1,6-Micheal addition process exhibits excellent chemo-and regioselectivity.To showcase the potential as a method for diversity-oriented drug discovery,the modification of numerous structurally complex bioactive molecules was also successfully performed.

Palladium-catalyzed sulfonylative coupling of benzyl(allyl)carbonates with arylsulfonyl hydrazides

An efficient palladium-catalyzed sulfonylative coupling for the synthesis of benzyl(allyl)sulfones from sulfonyl hydrazides and carbonates was developed.The novel methodology employs easily accessible chemical feedstocks including stable and readily available arylsulfonyl hydrazides and benzyl(allyl)carbonates.A variety of benzyl(allyl)sulfones could be obtained in good to excellent yields in the presence of Pd(dppf)Cl2 without additional base under mild conditions.

Palladium-catalyzed cross-coupling reaction of phenyl fluoroalkanesulfonates with organometallics

The palladium-catalyzed cross-coupling reaction of phenyl fluoroalkanesulfonates with organozinc,organotin and organoaluminum reagents in the presence of lithium chloride takes place to afford alkylbenzenes in good yields.However,the coupling reaction with organolithium and Grignard reagents proceeds unsatisfactorily with poor regioselectivity.On the basis of the isolation of an oxidative addition product of phenyl fluoroalkanesulfonate to palladium,a catalytic cycle in the reaction is suggested.

A novel alkyldehydroxylation of phenols Palladium-catalyzed reaction of phenyl fluoroalkanesulfonates with organoaluminum reagents

Recently we and others have reported that palladium could insert into the carbon-oxygen bond of phenyl fluoroalkanesulfonates,ArOSOR（1）,which could be convenientlyprepared from phenols.Thus,alkenylation and alkynylation of phenols could be accom-plished via the Heck reaction of 1,and moreover,some procedures for alkylation of phenolshave been provided by the cross-coupling reaction of 1 with organozincs and organotins,In order to extend the scope of the coupling reaction of 1,we are attracted by the palladium-