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An amidine base-containing polymer, polystyrene-bound 1,8-diazabicyclo[5.4.0]undec-7-ene (PS-DBU), proved to serve as a prominent catalyst support. The combined use of selected copper salts with PS-DBU in the catalytic hydrogenation of acetophenone qualifies DBU as beneficial to generate catalytically active species and stabilize them on the polymer. Catalyst preparation and characterization reveal that the active copper species is in a low-valent state and the nanosized particles possibly grow on the amidine structure. The high immobilization ability of PS-DBU almost entirely prohibited copper leaching to the product over six cycles of hydrogenation and catalyst recovery. The copper catalyst attached to PS-DBU specifically promotes the hydrogenation of various ketones and aldehydes under 10 atm of H2 at 90 °C to afford alcoholic products in satisfactory yields. [ABSTRACT FROM AUTHOR]

The front cover picture, provided by Bo Wang, Xinyan Wang, and Yuefei Hu, illustrates the characteristics of 1 ‐ copper(I) ‐ 2 ‐ phenylethyne in its preparation, properties and structure. By using its polymeric structure, the tandem reaction sequence of 1 ‐ Cu(I) ‐ alkyne with an azide (cycloaddition) and then an electrophile E+ (electrophilic substitution) can be controlled efficiently. Thus, a general method for the synthesis of 1,4,5 ‐ trisubstituted 1,2,3 ‐ triazoles was developed by simply stirring the mixture of a 1 ‐ copper(I) ‐ alkyne, an azide and an electroplile E+. Details can be found in the full paper on pages 401 – 407 (B. Wang, N. Liu, W. Chen, D. Huang, X. Wang, Y. Hu, Adv. Synth. Catal. 2015, 357, 401 – 407; DOI: 10.1002/adsc.201400471). [ABSTRACT FROM AUTHOR]

This paper describes the synthesis and structural characterization of two new one-dimensional coordination polymers involving 1,3-bis(4-pyridyl)propane ligand named {(μ-NCS)2[Cu(bpp)] ·dmf} n ( 1) and {[Cu(mebpy)(bpp)(dmso)](ClO4)2 ·dmso} n ( 2) (bpp = 1,3-bis(4-pyridyl)propane and mebpy = 4,4'-dimethyl-2,2'-bipyridine). These compounds were characterized by means of elemental analysis, thermal analysis (TG/DTA), vibrational spectroscopy (IR and Raman) and had their structures determined by single-crystal X-ray diffraction analysis. Compound 1 consists of CuN4 coordination spheres with bpp ligands in the unusual GG conformation coordinated in bridges between CuII centers to form a wavelike 1-D coordination polymer. On the other hand, in compound 2 the bpp ligand adopts the TT conformation in bridging mode extending the 1D cationic polymeric chain. [ABSTRACT FROM AUTHOR]

The Cover Feature shows that copper nanoparticles grown on polystyrene‐bound 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (PS‐DBU) can catalyze the hydrogenation of ketones and aldehydes. In their Full Paper, R. Watari et al. demonstrate that the PS‐DBU provides a suitable environment for the formation and stabilization of catalytically active Cu species. The prepared Cu nanoparticles on PS‐DBU exhibit high catalytic activity with negligible Cu leaching, robustness, good recyclability, and broad functionality tolerance. These results demonstrate the potential of PS‐DBU as an immobilizing support for transition‐metal catalysts for the first time. More information can be found in the Full Paper by R. Watari et al. on page 4501 in Issue 24, 2017 (DOI: 10.1002/cctc.201701316). [ABSTRACT FROM AUTHOR]

A series of new ( N′-substituted)-hydrazo-4-aryl-1,4-dihydropyridines was successfully synthesized via a facile one-pot catalytic pathway utilizing azines and propiolate esters as starting materials and a one-dimensional copper benzotriazole-based coordination polymer as catalyst. In the absence of catalyst, the corresponding 5-substituted 4,5-dihydropyrazoles were formed in moderate to high yields. Fine-tuning of the catalysts allowed us to gain more insights regarding the plausible reaction mechanism. [ABSTRACT FROM AUTHOR]

An unprecedented copper(II)-catalyzed enantioselective 1,3-dipolar [3+4] cycloaddition of azomethine imines with in situ formed azoalkenes has been realized. This strategy provides a facile access to biologically important 1,2,4,5-tetrazepine derivatives in high yield with exclusive regioselectivity and high stereoselectivity. Moreover, enantioenriched azomethine imines could be obtained via an efficient kinetic resolution using the same approach. [ABSTRACT FROM AUTHOR]

A facile synthesis of a diverse array of benzo[ b]fluorenone derivatives has been developed. The method involves a Cu0/Selectfluor-catalyzed tandem annulation of 1,6-enynes, which takes place under mild reaction conditions. For tert-butylethynyl-substituted 1,6-enynes, the major reaction pathway was a tandem annulation/C-C-bond-cleavage/fluorination process leading to fluorinated benzo[ b]fluorenones as the major products; tert-butyl-substituted benzo[ b]fluorenones were obtained as the minor products. For arylethynyl-substituted 1,6-enynes, the substrates underwent tandem annulations to give 5-aryl-substituted benzo[ b]fluorenones in moderate to excellent yields. For (trimethylsilyl)ethynyl-substituted 1,6-enynes, the reaction involved a tandem annulation/C-Si-bond-cleavage process to deliver 11 H-benzo[ b]fluoren-11-ones in moderate yields. [ABSTRACT FROM AUTHOR]

Hydrogenation of carbon dioxide to formate was achieved using copper (Cu) catalysts in the presence of strong organic bases including amidines and guanidines. Specifically, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) proved to be effective for the transformation of a 1:1 mixture of hydrogen and carbon dioxide into its formate salt under increased pressure in the presence of various Cu(I) and Cu(II) salts at 100 °C. A novel complex derived from copper iodide and DBU equally promoted the same reaction, indicating that DBU-Cu species are involved as real catalysts in this hydrogenation. [ABSTRACT FROM AUTHOR]

Chiral secondary allylboronates are obtained in high enantioselectivities and 1,6:1,4 ratios by the copper-catalyzed 1,6-boration of electron-deficient dienes with bis(pinacolato)diboron (B2(pin)2). The reactions proceed efficiently using catalyst loadings as low as 0.0049 mol %. The allylboronates may be oxidized to the allylic alcohols, and can be used in stereoselective aldehyde allylborations. This process was applied to a concise synthesis of atorvastatin, in which the key 1,6-boration was performed using only a 0.02 mol % catalyst loading. [ABSTRACT FROM AUTHOR]

Arylmethyl halides are readily synthesized via from the basic raw materials, even in green processes. They are used to replace their downstream products to prepare medicinally important 2-aryl benzimidazoles. CuBr-catalyzed synthesis of 2-aryl benzimidazoles from arylmethyl halides and 1,2-diaminoarenes via a one-pot domino reaction is developed. This new synthetic method is simple, practical and cost saving, and tolerates wide functional groups. A mechanism of CuBr-catalyzed aerobic oxidative domino reaction via a one-pot four-step process is proposed. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Neutral, iodido-containing copper(I) complexes [Cu( aNHC)2I] { aNHC = 1-benzyl-3-methyl-4-phenyl-1,2,3-triazol-5-ylidene (for 6) and 3-methyl-1-[2-(methylthio)phenyl]-4-phenyl-1,2,3-triazol-5-ylidene (for 7)} and cationic, halide-free copper(I) complexes [Cu( aNHC)2](BF4) { aNHC = 1-benzyl-3-methyl-4-phenyl-1,2,3-triazol-5-ylidene (for 8), 3-methyl-1,4-diphenyl-1,2,3-triazol-5-ylidene (for 9), 3-methyl-1-[2-(methylthio)phenyl]-4-phenyl-1,2,3-triazol-5-ylidene (for 10), and 1-mesityl-3-methyl-4-phenyl-1,2,3-triazol-5-ylidene (for 11)}, both containing two monodentate abnormal-carbene ligands ( aNHC), were synthesized from [Cu(CH3CN)4](BF4) and the corresponding triazolium salts. It was possible to selectively synthesize both kinds of complexes by simply variing the counter-anion of the triazolium salts and keeping the metal precursor the same. All complexes were characterized by elemental analysis and spectroscopic methods. 6 and 11 were studied with single-crystal X-ray diffraction analyses. In 6, the copper(I) center is tricoordinated, and its geometry is in between trigonal planar and T-shaped. In halide-free 11, the copper(I) center is linearly coordinated by two abnormal-carbene ligands. All complexes were tested as catalysts in the Huisgen [3+2] cycloaddition reaction between azides and alkynes, and they showed excellent efficiencies under neat conditions. A comparison between the efficiencies of the halide-containing complexes 6 and 7 and the halide-free cases 8- 11, shows that the halide-free Cu- aNHC complexes are significantly more efficient than their halide-containing counterparts. The best catalyst was used for a substrate screening by utilizing a variety of azides and a couple of alkynes. The efficiency of the catalyst was maintained with loadings as low as 0.005 mol-%. Mechanistic studies were carried out as well. [ABSTRACT FROM AUTHOR]