Light‐Promoted Nickel Catalysis: Etherification of Aryl Electrophiles with Alcohols Catalyzed by a NiII‐Aryl Complex

A highly effective C?O coupling reaction of (hetero)aryl electrophiles with primary and secondary alcohols is reported. Catalyzed by a Ni^II‐aryl complex under long‐wave UV (390–395 nm) irradiation in the presence of a soluble amine base without any additional photosensitizer, the reaction enables the etherification of aryl bromides and aryl chlorides as well as sulfonates with a wide range of primary and secondary aliphatic alcohols, affording synthetically important ethers. Intramolecular C?O coupling is also possible. The reaction appears to proceed via a Ni^I–Ni^III catalytic cycle.     

General and Mild Ni0‐Catalyzed α‐Arylation of Ketones Using Aryl Chlorides

A general methodology for the α‐arylation of ketones using a nickel catalyst has been developed. The new well‐defined [Ni(IPr*)(cin)Cl] ( 1 c ) pre‐catalyst showed great efficiency for this transformation, allowing the coupling of a wide range of ketones, including acetophenone derivatives, with various functionalised aryl chlorides. This cinnamyl‐based Ni–N‐heterocyclic carbene (NHC) complex has demonstrated a different behaviour to previously reported NHC‐Ni catalysts. Preliminary mechanistic studies suggest a Ni⁰/Ni^II catalytic cycle to be at play.     

Light-Promoted Nickel Catalysis: Etherification of Aryl Electrophiles with Alcohols Catalyzed by a NiII-Aryl Complex

A highly effective C−O coupling reaction of (hetero)aryl electrophiles with primary and secondary alcohols is reported. Catalyzed by a Ni^II-aryl complex under long-wave UV (390–395 nm) irradiation in the presence of a soluble amine base without any additional photosensitizer, the reaction enables the etherification of aryl bromides and aryl chlorides as well as sulfonates with a wide range of primary and secondary aliphatic alcohols, affording synthetically important ethers. Intramolecular C−O coupling is also possible. The reaction appears to proceed via a Ni^I–Ni^III catalytic cycle.     

Synthesis of Phenols: Organophotoredox/Nickel Dual Catalytic Hydroxylation of Aryl Halides with Water

A highly effective hydroxylation reaction of aryl halides with water under synergistic organophotoredox and nickel catalysis is reported. The OH group of the resulting phenols originates from water, following deprotonation facilitated by an intramolecular base group on the ligand. Significantly, aryl bromides as well as less reactive aryl chlorides served as effective substrates to afford phenols with a wide range of functional groups. Without the need for a strong inorganic base or an expensive noble‐metal catalyst, this process can be applied to the efficient preparation of diverse phenols and enables the hydroxylation of multifunctional pharmaceutically relevant aryl halides.     

Metal‐Catalyzed Dealkoxylative CarylC Cross‐Coupling—Replacement of Aromatic Methoxy Groups of Aryl Ethers by Employing a Functionalized Nucleophile

The direct replacement of aromatic methoxy groups with activated carbon nucleophiles would give rise to novel synthetic pathways for targeted and diversity‐oriented syntheses. We demonstrate here that this transformation can be achieved in a one‐step reaction involving a bifunctional organolithium nucleophile in combination with a C_Ar? OMe bond‐cleaving nickel catalyst. The resulting products are stable, α‐CH active, and suitable for various further modifications.     

Homolytic Cleavage of a B−B Bond by the Cooperative Catalysis of Two Lewis Bases: Computational Design and Experimental Verification

Density functional theory (DFT) investigations revealed that 4‐cyanopyridine was capable of homolytically cleaving the B?B σ bond of diborane via the cooperative coordination to the two boron atoms of the diborane to generate pyridine boryl radicals. Our experimental verification provides supportive evidence for this new B?B activation mode. With this novel activation strategy, we have experimentally realized the catalytic reduction of azo‐compounds to hydrazine derivatives, deoxygenation of sulfoxides to sulfides, and reduction of quinones with B₂(pin)₂ at mild conditions.     

Lewis Acid Mediated Tandem Reaction of Propargylic Alcohols to Tetrazoles Involving CO‐ and CC‐Bond Cleavage Reactions and a CN‐Bond Formation

A novel and direct synthesis of 1‐aryl‐5‐arylvinyl‐tetrazoles from easily prepared propargylic alcohols and TMSN₃ is developed in the presence of TMSCl under mild conditions (TMS=trimethylsilyl). The process involves an allenylazide intermediate, followed by a C?C‐bond cleavage and C?N‐bond formation to afford the desired products. Moreover, this method offers a good functional‐group applicability and can be scaled‐up to grams (yield up to 85 %).     

Nickel‐Promoted Highly Regioselective Carboxylation of Aryl Ynol Ether and Its Application to the Synthesis of Chiral β‐Aryloxypropionic Acid Derivatives

Nickel(0)‐promoted carboxylation of aryl ynol ether proceeded in a highly regioselective manner to produce α‐substituted‐β‐aryloxyacrylic acid derivatives. The α‐substituted‐β‐aryloxyacrylic acids were transformed into the corresponding β‐aryloxypropionic acid derivative as an optically active form via rhodium‐catalyzed asymmetric hydrogenation.     

Ab Initio Molecular Dynamics Study of Hydrogen Cleavage by a Lewis Base [tBu3P] and a Lewis Acid [B(C6F5)3] at the Mesoscopic Level—Dynamics in the Solute–Solvent Molecular Clusters

With the help of state‐of‐the‐art ab initio molecular dynamics methods, we investigated the reaction pathway of the {tBu₃P + H₂ + B(C₆F₅)₃} system at the mesoscopic level. It is shown that: i) the onset of H₂ activation is at much larger boron???phosphorus distances than previously thought; ii) the system evolves to the product in a roaming‐like fashion because of quasi‐periodic nuclear motion along the asymmetric normal mode of P???H?H???B fragment; iii) transient configurations of a certain type are present despite structural interference from the solvent; iv) transient‐state configurations with sub‐picosecond lifetime have potentially interesting infrared activity in the organic solvent (toluene) as well as in the gas phase. The presented results should be helpful for future experimental and theoretical studies of frustrated Lewis pair (FLP) activity.     

Exploring Te–Te Bond Cleavage with Palladium(II): Synthesis,X‐ray Structural Characterization,and Optical Features of Tellurolate and Telluro‐Ether Complexes of Palladium(II)

The focus of this study was to explore reactions of (RTe)₂ with palladium(II) salts. These reactions led to Te–Te bond cleavage and the formation of three tellurolate‐bridged dinuclear complexes and a mononuclear telluro‐ether palladium(II) complex. The methodologies used yielded single source precursors for interesting materials. UV/vis spectroscopy results supported the measured optical bandgap for the complexes in the solid state. A study on the structure of all complexes in the solid state was carried out using single‐crystal X‐ray diffraction. Other analytical methodologies, such as elemental analysis and infrared spectroscopy, were also used for the characterization of the complexes.     

Nickel‐Catalyzed Cross‐Coupling of Functionalized Difluoromethyl Bromides and Chlorides with Aryl Boronic Acids: A General Method for Difluoroalkylated Arenes

Transition‐metal‐catalyzed difluoroalkylation of aromatics remains challenging despite the importance of difluoroalkylated arenes in medicinal chemistry. Herein, the first successful example of nickel‐catalyzed difluoroalkylation of aryl boronic acids is described. The reaction allows access to a variety of functionalized difluoromethyl bromides and chlorides, and paves the way to highly cost‐efficient synthesis of a wide range of difluoroalkylated arenes. The notable features of this protocol are its high generality, excellent functional‐group compatibility, low‐cost nickel‐catalyst, and practicality for gram‐scale production, thus providing a facile method for applications in drug discovery and development.     

CuI-catalyzed Coupling Reactions of Aryl Iodides with Amides Using L-Proline and KF/Al2O3

An efficient experimentally simple and inexpensive catalyst system for the selective amidation of aryl iodides using 15 mol% of CuI as catalyst, 15 mol% of L-proline as ligand and KF/Al2O3 as a base in toluene is described.     

氰尿酸镍的晶体结构

标题化合物Ｎｉ（Ｃ＿３Ｈ＿２Ｎ＿３Ｏ＿３）＿２（Ｈ２Ｏ）＿４属正交晶系，空间群为Ｆｍｍｍ（编号６９）。晶胞参数：ａ＝７．２８２（４），ｂ＝１２．０５７（２），ｃ＝１６．０７２（２），Ｖ＝１４１１（１），Ｄ＿ｃ＝１．８２ｇ／ｃｍ￣３，Ｚ＝４，Ｍ＿ｒ＝３８６．８９，λ（ＭｏＫα）＝０．７１０６９，μ＝１４．４３ｃｍ￣（－１），Ｆ（０００）＝７９２。最终偏离因子Ｒ＝０．０４５，Ｒ＿ｗ＝０．０６０。独立可观测点数（Ｉ≥３σ（Ｉ））为３８５个。在配合物中，镍离子与来自氰尿酸的两个氮原子和来自水分子的四个氧原子配位。     

Syntheses and Crystal Structures of Cobalt(II) and Nickel(II) Coordination Polymers with 3-Aminobenzoic Acid Ligand

1 INTRODUCTION Much research interest has been focused on metal- organic coordination polymers in past years because of the structural and topological novelty of these compounds and their potential applications as func- tional materials, such as catalyst, ion-exchange, gas sorption, optical material and molecule-based ma- gnet[1~6]. In this field, many organic bridging ligands such as bipyridine, polyaromatic carboxylate and re- lated species have been used to produce various types of met…     

BiCl3‐catalyzed carbon‒carbon cross‐coupling of organoboronic acids with aryl iodides

A procedure for BiCl₃‐catalyzed carbon‐carbon cross‐coupling reaction of organoboronic acids with aryl iodides is described. This protocol has a wide substrate scope and uses an inexpensive and non‐toxic catalyst. Copyright © 2013 John Wiley & Sons, Ltd.