Search

In this study, a novel La(III)-based two-dimensional (2D) metal-organic framework, [La

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01 mol%).

Novel N-heterocyclic carbene-palladium(II) complexes using 2-picolinic acid as the ancillary ligand have been successfully developed under mild conditions. Their catalytic activity in organic synthesis has been initially tested in the Buchwald-Hartwig amination of secondary and primary amines with aryl chlorides. Various substituents on both substrates can be tolerated, giving the desired coupling products in good to almost quantitative yields. The minimum catalyst loading can be 0.01 mol%, implying their potential application toward industrial processes.

A series of N-heterocyclic carbene-palladium(II) chlorides-1-methylindazole and -1-methylpyrazole complexes was successfully synthesized and fully characterized by X-ray single crystal diffraction. In addition, initial investigations of their catalytic activity showed that they were efficient catalysts in the C–N coupling of primary and secondary amines with aryl chlorides at low catalyst loadings.

The first example of palladium-catalyzed Suzuki-Miyaura coupling between benzyl sulfonates and arylboronic acids was reported in this paper. In the presence of a well-defined, air-stable and easily available NHC-Pd(II)-Im complex, all reactions worked well to give the desired products in good to almost quantitative yields under the optimal conditions. Electron-rich, -neutral, -poor and sterically-hindered substituents on both substrates are tolerated in such transformation, providing a convenient, efficient and alternative method for the synthesis of diarylmethanes.

A well-defined NHC-Pd(II)-Im complex 1 showed efficient catalytic activity toward the allyl-aryl coupling of allylic alcohols with arylboronic acids in neat water. Under the optimal reaction conditions, all reactions proceeded smoothly to give the corresponding coupling products in moderate to high yields.

The palladium-catalyzed chemoselective mono-amination of dichlorobenzenes was reported in this paper. Under the suitable conditions, all reactions involving the three isomers of dichlorobenzenes with various secondary and primary amines in the presence of a well-defined N-heterocyclic carbene-palladium(II)-2-methyl-4,5-dihydrooxazole complex, gave the desired mono-aminated products in moderate to high yields as the major or sole one.

A transition-metal-free, C–N bond-formation reaction between tertiary amines and aryl halides is reported. Under the optimal conditions, various aromatic and aliphatic tertiary amines react with aryl halides, including iodides, bromides, and chlorides, to give mono-aminated products, N,N-dialkylanilines and N-alkyl-N-arylanilines, in good to high yields. Based on the experimental results, the reaction is believed to occur via an aryne intermediate derived from the aryl halide.

A series of novel N-heterocyclic carbene–palladium(II)–4,5-dihydrooxazole (NHC-PdII-Ox) complexes 3 were successfully synthesized from commercially available imidazolium salts 1, PdCl2, and 4,5-dihydrooxazoles 2 in a one-step process, and these complexes showed efficient catalytic activity toward the amination of aryl chlorides. Both secondary and primary amines were tolerated under the same reaction conditions. Under the optimal reaction conditions, the expected coupling products were obtained in moderate to high yields.

A series of N-heterocyclic carbene–PdCl2–imidazole [NHC–Pd(II)–Im] complexes were synthesized and the structure of most of them was unambiguously determined by X-ray single-crystal diffraction. The structure–activity relationship of these complexes was investigated for the Suzuki–Miyaura coupling between 4-methoxyphenyl chloride and phenylboronic acid, and the effect of the NHCs and Im moieties were fully discussed. The sterically hindered IPr-based complex showed the highest catalytic activity. Copyright © 2013 John Wiley & Sons, Ltd.

Dialkylformamides are excellent N-sources in the amination of benzyl chlorides when catalysed by a NHC-Pd(II)-Im complex. In the presence of NaOH and the catalyst, variously substituted benzyl chlo...

PdCl2(1-methylimidazole)2 was an effective catalyst in neat water for the Suzuki–Miyaura and Mizoroki–Heck reactions of aryl bromides and iodides with, respectively, arylboronic acids and acrylic acid. Under optimal conditions, the products, variously substituted biphenyls and monosubstituted trans-cinnamic acids, respectively, were formed in good to almost quantitative yields.

A Pd(II)-catalyzed oxidative Heck-type reaction of triarylphosphines with alkenes via carbon–phosphorus bond cleavage was reported. Under the optimal reaction conditions, most reactions proceeded smoothly to give the expected coupling products in acceptable to high yields.

A new type of N-heterocyclic carbene–PdCl2–(iso)quinoline complexes 3 were successfully achieved in acceptable to good yields from easily available starting materials under mild conditions, and their structures were unambiguously confirmed using X-ray single crystal diffraction. Furthermore, their catalytic activity toward Buchwald–Hartwig arylamination of aryl chlorides with primary and secondary amines was fully tested. Under the optimal reaction conditions, the expected arylated amines can be obtained in high to excellent yields at low catalyst loadings (0.005–0.05 mol%). It may be worth noting here that comparison of these complexes with other well-defined and easily available NHC–Pd(II) complexes bearing different N-containing ancillary ligands was also carried out, showing their superior catalytic activity over all others.

A series of N-heterocyclic carbene-palladium(II) chlorides-1-methylindazole and -1-methylpyrazole complexes was successfully synthesized and fully characterized by X-ray single crystal diffraction. In addition, initial investigations of their catalytic activity showed that they were efficient catalysts in the C–N coupling of primary and secondary amines with aryl chlorides at low catalyst loadings.

A well-defined N-heterocyclic carbene (NHC)–palladium chloride–imidazole complex exhibited high catalytic activity in the coupling reaction of arylboronic acids with carboxylic acid anhydrides in pure water under mild conditions. Under the optimal conditions, all reactions gave the desired coupling products in moderate to high yields.

A novel dinuclear Pd(II)–N-heterocyclic carbene complex derived from proline was successfully synthesized and its structure was confirmed unambiguously by X-ray single-crystal diffraction. Furthermore, the complex was found to be a good catalyst in the Mizoroki–Heck reaction of aryl iodides and bromides with acrylic acid performed in pure water. Copyright © 2012 John Wiley & Sons, Ltd.

A new type of well-defined N-heterocyclic carbene (NHC)-palladium chloride-imidazole complexes derived from IPr HCl or IMes HCl, PdCl2 and 1-methylimidazole exhibits high catalytic activity in the room-temperature Suzuki-Miyaura coupling reactions of aryl or heteroaryl chlorides. Moreover, the large-scale (20.0 mmol) couplings in the presence of 0.01 mol% catalyst loading can also give the corresponding coupling products in high yields.

Palladium(II)- N -heterocyclic carbene complex 1 derived from proline has been proved to be a highly effective catalyst in the Suzuki–Miyaura coupling reaction of aryl iodides and bromides with arylboronic acids in water at room temperature. The reactions are tolerant towards various functional groups in the substrates. Moreover, the complex 1 -catalyzed medium-scale (10.0 mmol) Suzuki–Miyaura reactions were also carried out and it was found that the complex was also effective enough in these cases.

2,2′-Diamino-6,6′-dimethylbiphenyl (L1) was found to be a good ligand in the CuI-catalyzed Sonogashira coupling reaction of various aryl iodides and bromides with terminal alkynes. Under suitable c...

Cleavage of a CN bond of imidazolium salt derived from N-phenyl-substituted proline was observed in this laboratory. A novel imidazole-coordinated monodentate NHC–Pd(II) complex 5 was obtained as the sole product in good yield in the reaction of imidazolium salt 4 with Pd(OAc)2 in refluxing THF. The structure of complex 5 was determined unambiguously by an X-ray diffraction. The complex was found to be a good catalyst in the cross-coupling reaction of arylboronic acids with carboxylic acid anhydrides in water at room temperature. Copyright © 2011 John Wiley & Sons, Ltd.

N-Heterocyclic carbene–rhodium(I) complexes derived from N-benzyl substituted proline have been successfully synthesized and were found to be efficient catalysts for the 1,4-conjugate addition of arylboronic acids to enones in neat water at 40 °C. Under the optimal reaction conditions, all reactions gave the addition products in good to high yields.

N-Heterocyclic carbene-palladium(II)-1-methylimidazole [NHC-Pd(II)-Im] complex 1 showed efficient catalytic activity toward α-arylation of symmetric dialkyl ketones under mild conditions. It was found that the ratio of aryl chlorides and ketones drastically affected the reaction. When the ratio of aryl chlorides and ketones was 1:2, mono-arylated products can be obtained in good to high yields as the sole; while that of aryl chlorides and ketones was changed to 1:0.7, di- and mono-arylated products were obtained in good to high total yields at the same time, with the former as the major.

CuO-catalyzed Suzuki–Miyaura cross-coupling reactions of arylboronic acids with aryl iodides and bromides using 2,2′-diamino-6,6′-dimethylbiphenyl as the ligand are described in the paper. Under suitable conditions, all reactions gave the desired coupling products in moderate to excellent yields.

2,2′-Diamino-6,6′-dimethylbiphenyl was found to be an efficient ligand in the palladium-catalyzed Suzuki–Miyaura coupling reactions of aryl iodides, bromides, and chlorides and Mizoroki–Heck reactions of aryl iodides and bromides. Under appropriate conditions, all reactions gave the desired products in moderate to excellent yields. The ligand is inexpensive, air-stable and easy to available.

Lewis acid or Brønsted acid catalyzed reactions of vinylidene cyclopropanes (VDCPs), 1, with activated carbon-nitrogen, nitrogen-nitrogen, and iodine-nitrogen double-bond-containing compounds have been thoroughly investigated. We found that pyrrolidine and 1,2,3,4-tetrahydroquinoline derivatives can be formed in good yields in the reactions of VDCPs 1 with ethyl (arylimino)acetates 2 by a [3+2] cycloaddition or intramolecular Friedel-Crafts reaction pathway. Based on these results, we found that activated carbon-nitrogen and nitrogen-nitrogen double-bond-containing compounds, such as N-toluene-4-sulfonyl (N-Ts) imines 5 and diisopropylazodicarboxylate (7), can also react with VDCPs 1 to give [3+2] cycloaddition products in moderate to good yields in the presence of a Lewis acid. When N-tert-butoxycarbonyl aldimine 9 was used as the substrate, six-membered cycloaddition products 10 and 11 were formed in moderate yields in the presence of a Brønsted acid, trifluoromethanesulfonic acid (TfOH). The reactions of VDCPs 1 with N-Ts-iminophenyliodinane (12) were also carried out in the presence of (CuOTf)(2)C(6)H(6) and it was found that nitrogen-containing indene derivatives 13 were obtained, rather than the aziridination products. Plausible mechanisms for all of these transformations are discussed, based on the obtained results.

Vinylidenecyclopropanes 1 can undergo intramolecular rearrangement to give the corresponding functionalized 1,2-dihydronaphthalenes in the presence of gold catalyst under mild conditions. A plausible rearrangement mechanism has been proposed on the basis of control experiments.

A new type of N-heterocyclic carbene–PdCl2–(iso)quinoline complexes 3 were successfully achieved in acceptable to good yields from easily available starting materials under mild conditions, and their structures were unambiguously confirmed using X-ray single crystal diffraction. Furthermore, their catalytic activity toward Buchwald–Hartwig arylamination of aryl chlorides with primary and secondary amines was fully tested. Under the optimal reaction conditions, the expected arylated amines can be obtained in high to excellent yields at low catalyst loadings (0.005–0.05 mol%). It may be worth noting here that comparison of these complexes with other well-defined and easily available NHC–Pd(II) complexes bearing different N-containing ancillary ligands was also carried out, showing their superior catalytic activity over all others.

[reaction: see text] A number of pyrrolidine and 1,2,3,4-tetrahydroquinoline derivatives are prepared selectively in moderate to good yields by the reaction of arylvinylidenecyclopropanes 1 with ethyl (arylimino)acetates 2 in the presence of Lewis acid depending on the electronic nature both of 2 and R1 or R2 aromatic groups of 1.

A well-defined NHC-Pd(II)-Im complex 1 showed efficient catalytic activity toward the allyl-aryl coupling of allylic alcohols with arylboronic acids in neat water. Under the optimal reaction conditions, all reactions proceeded smoothly to give the corresponding coupling products in moderate to high yields.

Reactions of vinylidenecyclopropanes with diaryl diselenide catalyzed by iodosobenzene diacetate produced the corresponding addition products 4 in moderate to good yields under mild conditions. The further transformation of 4 to the corresponding methylenecyctopropanes 5 has been disclosed in the presence of hydrogen peroxide (H 2 O 2 ) in toluene.

The atom transfer radical polymerization (ATRP) of hexadecyl acrylate (HDA) was carried out inN,N-dimethylformamide (DMF) in the presence of CuSCN/N,N,N′,N″,N″-pentamethyldiethylenetriamine (PMDETA). The results indicate that the polymerization is well-controlled: a linear increase of molecular weights occurs with respect to conversion and the polydispersities are relatively low. In particular, the use of CuSCN as the catalyst resulted in faster polymerization rates for hexadecyl acrylate than did those using either CuBr or CuCl; the polydispersity, however, was larger than those obtained in the cases when CuBr and CuCl were used. In addition, we report the thermodynamic data and activation parameters for the solution ATRP of hexadecyl acrylate.

A well-defined NHC–Pd(II)–Im complex was proved to be an efficient catalyst for the Hiyama reaction of a variety of aryl chlorides with aryltrimethoxysilanes. Under the optimal conditions, all reactions took place smoothly to give the corresponding coupling products in moderate to high yields.

A total of 11 NHC-Pd(II)-imidazole complexes are synthesized and tested with respect to their catalytic activity.

A high yielding Suzuki—Miyaura and Mizoroki—Heck coupling reaction with water as solvent and PdCl2(1-Methylimidazole)2 complex as catalyst is shown.

An easily available N-heterocyclic carbene–palladium(II)–1-methylimidazole complex 1 showed efficient catalytic activity in the Suzuki–Miyaura coupling of benzylic chlorides with arylboronic acids or potassium phenyltrifluoroborate in neat water under mild conditions, providing an alternative method for the synthesis of diarylmethane derivatives, which widely exist in molecules with pharmaceutical activities and are also frequently found as subunits in supramolecules. Under the optimal conditions, all reactions performed well to give the desired products in moderate to almost quantitative yields in an environmentally benign medium within 12 h, extending their applications toward potentially industrial processes.

A Pd(II)-catalyzed oxidative Heck-type reaction of triarylphosphines with alkenes via carbon–phosphorus bond cleavage was reported. Under the optimal reaction conditions, most reactions proceeded smoothly to give the expected coupling products in acceptable to high yields.

An easily available N-heterocyclic carbene–palladium(II)–1-methylimidazole complex 1 showed efficient catalytic activity in the Suzuki–Miyaura coupling of benzylic chlorides with arylboronic acids or potassium phenyltrifluoroborate in neat water under mild conditions, providing an alternative method for the synthesis of diarylmethane derivatives, which widely exist in molecules with pharmaceutical activities and are also frequently found as subunits in supramolecules. Under the optimal conditions, all reactions performed well to give the desired products in moderate to almost quantitative yields in an environmentally benign medium within 12 h, extending their applications toward potentially industrial processes.

The application of a NHC-metal complex in pure water, which is not developed very popularly to date, is presented for the title reaction.

The new palladium chloride-imidazole complex exhibits high catalytic activity in the room-temperature Suzuki-Miyaura coupling reactions of aryl chlorides.

Palladium(II)- N -heterocyclic carbene complex 1 derived from proline has been proved to be a highly effective catalyst in the Suzuki–Miyaura coupling reaction of aryl iodides and bromides with arylboronic acids in water at room temperature. The reactions are tolerant towards various functional groups in the substrates. Moreover, the complex 1 -catalyzed medium-scale (10.0 mmol) Suzuki–Miyaura reactions were also carried out and it was found that the complex was also effective enough in these cases.

2,2′-Diamino-6,6′-dimethylbiphenyl (L1) was found to be a good ligand in the CuI-catalyzed Sonogashira coupling reaction of various aryl iodides and bromides with terminal alkynes. Under suitable c...

2,2′-Diamino-6,6′-dimethylbiphenyl was found to be an efficient ligand in the palladium-catalyzed Suzuki–Miyaura coupling reactions of aryl iodides, bromides, and chlorides and Mizoroki–Heck reactions of aryl iodides and bromides. Under appropriate conditions, all reactions gave the desired products in moderate to excellent yields. The ligand is inexpensive, air-stable and easy to available.

Highly stereo- and regioselective carbolithiation reactions of vinylidenecyclopropanes 1 were realized by treatment with lithium diisopropylamide (LDA) in THF and by quenching with various electrophiles such as aryl or aliphatic aldehydes, ketones, enones or propargyl bromide. Transformation of these adducts such as vinylcyclopropenes and allenols was also performed in the presence of Lewis acid or Bronsted acid to provide the fused and conjugated aromatic products in good to high yields under mild conditions.

Vinylidenecyclopropanes 1 can undergo intramolecular rearrangement to give the corresponding functionalized 1,2-dihydronaphthalenes in the presence of gold catalyst under mild conditions. A plausible rearrangement mechanism has been proposed on the basis of control experiments.