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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 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 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.

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.

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.

In the presence of a new complex, cross-coupling reaction of arylboronic acids with carboxylic acid anhydrides results in formation of diarylketones, mostly 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...

State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, P. R. China, College of Chemistry and Materials Engineering, Wenzhou University, Chashan University Town, Wenzhou, Zhejiang Province 325035, P. R. China, and Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai, Osaka 599-8531, Japan

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.

A novel domino carbolithiation reaction of vinylidenecyclopropanes 1 with but-3-yn-2-one and 1-phenylprop-2-yn-1-one by treating with LDA in THF was observed to give the corresponding adducts in moderate to good yields. The scope and limitations as well as the plausible mechanism have been discussed on the basis of control experiments.

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.

Highly selective addition reaction of vinylidenecyclopropanes 1 was realized by treatment with LDA in THF and quenching with aldehydes, ketones, and enones. A number of vinylcyclopropenes, allenols, and 1,3-enynes were obtained selectively in moderate to good yields depending on the nature of different electrophiles.

AlCl3-mediated tandem Friedel–Crafts reaction of vinylidenecyclopropanes with acyl chlorides produced the corresponding 1-[2-(2,2-diarylvinyl)-1-phenyl-3H-inden-5-yl]ethanone derivatives in moderate to good yields under mild conditions within short reaction time.

A number of functionalized tetrahydrofuran and 3,6-dihydropyran derivatives are prepared selectively in moderate to good yields by the reactions of vinylidenecyclopropanes with activated carbonyl compounds in the presence of Lewis acid.

A series of naphthalene, indene, and 6aH-benzo[c]fluorene derivatives are synthesized by intramolecular rearrangement of vinylidenecyclopropanes using a heterogeneous solid acid catalyst, montmorillonite K-10, under mild reaction conditions in good to excellent yields. The solid acidic catalyst, montmorillonite K-10, can be recovered and reused.

[structure: see text]. Iodobenzene diacetate-mediated reactions of methylenecyclopropanes 1, vinylidenecyclopropanes 2, and a methylenecyclobutane 3a with phthalhydrazide give the corresponding [3+2] cycloaddition products in good yields under mild conditions. In these reactions, phthalhydrazide was transformed to a 1,3-dipole intermediate in the presence of iodobenzene diacetate. A plausible reaction mechanism has been proposed.

Pd(PPh3)4-catalyzed reactions of vinylidenecyclopropanes 1 with acetic acid proceeded smoothly at 80 °C in toluene to give the corresponding acetylated dienes 2 in moderate to good yields in the presence of DPEphos ligand. The plausible mechanism is proposed on the basis of the control and deuterium labeling experiments.

An interesting rearrangement of arylvinylidenecyclopropanes having three substituents at the 1- and 2-positions of the corresponding cyclopropane catalyzed by Lewis acids to give 6aH-benzo[c]fluorine derivatives via a double intramolecular Friedel-Crafts reaction or to give an indene derivative via an intramolecular Friedel-Crafts reaction is described.