Density Functional Theory Study on (Cl2GaN3)n(n=1–4) Clusters

The molecular geometries, vibrational properties, and thermodynamic properties of the clusters (Cl₂GaN₃)_n(n=1–4) have been predicted at the B3LYP/6‐311+G* level. The optimized clusters (Cl₂GaN₃)_n (n=2–4) all possess cyclic structures containing Ga N_α Ga linkages. The relationships between geometrical parameters and oligomerization degree n are discussed. The gas‐phase structures of the trimers prefer to exist in boat‐twisting conformation. As for the tetramer, the S₄ symmetry structure is the most stable. The infrared spectra are obtained and assigned by vibrational analysis. Thermodynamic properties derived from the infrared spectra on the basis of statistical thermodynamic principles are linearly correlated with the oligomerization degree n as well as the temperature. Meanwhile, thermodynamic analysis of the gas‐phase reaction suggests that the oligomerization is exothermic and favorable under high temperature.     

Commercial drug norfloxacin as a novel ligand for the copper‐catalyzed N‐arylation of imidazole with aryl halides

Norfloxacin was used as an efficient ligand for the CuBr‐catalyzed C‐N coupling reaction of imidazole and aryl halides. The protocol presented good functional group compatibility, permitting many aryl halides to react with imidazole to form the desired products in good to excellent yields.     

Efficient pyridylbenzamidine ligands for palladium‐catalyzed Suzuki–Miyaura reaction

A series of pyridylbenzamidine ligands were applied in palladium‐catalyzed Suzuki–Miyaura reactions and the effect of ligand on catalytic properties was evaluated. Under the optimization conditions, the bulky and electron‐donating nitrogen donor ligands were successfully used to catalyze the reaction of a variety of aryl bromides and aryl chlorides with arylboronic acid, giving the desired products in moderate to high yields. Copyright © 2012 John Wiley & Sons, Ltd.     

The Aryl Sulfide Synthesis via Sulfide Transfer

Aryl sulfides are in great demands in drugs and materials sciences. To avoid using nucleophilic and noxious thiols, many efforts have been focused on exploring novel sulfide resources. Herein, a reductive Pd-catalyzed, Ni-mediated method to synthesize aryl sulfides via a sulfide transfer reaction is developed. The utility and scope of this reaction is exemplified by various aryl electrophiles and aryl sulfides. Mechanistic studies reveal two competing catalytic cycles of sulfide transfer and aryl transfer in this reaction, where the former one is favored over the later one because of the large energy barrier difference during the transmetalation. Moreover, two important chemicals are late-stage functionalized by this method, exhibiting the potential applications in drugs and materials science.     

Palladium complex containing two sterically hindered ligands as highly efficient catalyst for Suzuki–Miyaura reaction

A new palladium(II) complex containing two sterically hindered ligands, a P,P‐bonded diphosphine and N,N‐bonded Schiff base, within the same coordination sphere has been synthesized and investigated as a catalyst for the Suzuki–Miyaura cross‐coupling reactions of aryl halides with arylboronic acids. The reaction was highly efficient with aryl bromides in water at room temperature and aryl chlorides in dimethylformamide under relatively mild conditions. Excellent yields of coupling products were obtained for a wide range of aryl halides including heteroaryl halides with a low loading of catalyst. Copyright © 2015 John Wiley & Sons, Ltd.     

Benedict's solution/ vitamin C: An alternative catalytic protocol for the synthesis of regioselective‐1,4‐disubstituted‐1H‐1,2,3‐triazoles at room temperature

A novel and highly efficient method for the synthesis of 1,4‐disubstituted‐1H‐1,2,3‐triazoles by copper‐catalyzed azide‐alkyne cycloaddition has been developed. This economic and sustainable protocol uses a readily available Benedict's solution/Vitamin C catalyst system affording a wide range of 1,4‐disubstituted‐1H‐1,2,3‐triazoles under mild conditions.     

Synthesis of cinnamyl substituted dihydrofuranones by the Heck cross-coupling reaction

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Copper-Mediated Fluorination of Aryl Trisiloxanes with Nucleophilic Fluoride

A method for the nucleophilic fluorination of heptamethyl aryl trisiloxanes to form fluoroarenes is reported. The reaction proceeds in the presence of Cu(OTf)₂ and KHF₂ as the fluoride source under mild conditions for a broad range of heptamethyltrisiloxyarenes with high functional group tolerance. The combination of this method with the silylation of aryl C−H bonds enables the regioselective fluorination of non-activated arenes controlled by steric effects following a two-step protocol.     

Taking diazo transfer to water: α-diazo carbonyl compounds from in situ generated mesyl azide

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Copper catalyzed aryl amidation between Nα-Fmoc-protected amino-acid azides and aryl boronic acids

Abstract

A simple and efficient method for the synthesis of aryl amides via oxidative copper-catalyzed coupling of commercially available aryl boronic acids and bench stable N^α-protected amino-acid azides is reported. The potential utility of this protocol is demonstrated through a survey of diversely substituted aryl boronic acids and several side-chain functionalized amino-acid azides, leading to the preparation of the desired amidated products in good to excellent yields. This amide synthesis is suitable for the preparation of amides (such as peptide aryl amides and sterically hindered amino acids) that are not or hardly accessible via classical approaches.