An Indium(III)‐Catalyzed Synthesis of 4,4‐Dichloro‐1‐aryl‐N‐alkyl‐1‐yn‐3‐amines via an Intermolecular C(sp2)?C(sp) Bond Formation

This paper demonstrates an indium(III) triflate‐catalyzed reaction of electron‐deficient α,α‐dichloroaldimines with terminal alkynes leading to a rapid and selective access to highly functionalized propargylic amines in good to excellent yields. The dichloromethylene moiety of the aldimine acts as an activating group to accomplish this transformation under very mild conditions.     

Nickel(II)‐Mediated Regioselective C?H Monoiodination of Arenes and Heteroarenes by using Molecular Iodine

The 8‐aminoquinoline‐directed, nickel(II)‐mediated ortho‐iodination of benzamides using molecular iodine has been developed. The process is highly regioselective and furnishes only monoiodinated products. A broad range of arenes and heteroarenes with diverse functional groups provided monoiodinated products in good to excellent yields.

     

Transition Metal‐Mediated Direct C?H Arylation of Heteroarenes Involving Aryl Radicals

This review gives an overview of the generation of aryl radicals, mediated by transition metals, and their use for the C H arylation of heteroarenes. The different sources of aromatic derivatives able to generate aryl radicals via a metal‐assisted reduction or oxidation are discussed, with a critical view of the developed systems. The radical arylations of nitrogen‐, oxygen‐ or sulfur‐containing heterocycles are then described and mechanistic considerations are discussed as well.

     

Cross‐Coupling of Heteroarenes by C?H Functionalization: Recent Progress towards Direct Arylation and Heteroarylation Reactions Involving Heteroarenes Containing One Heteroatom

In recent years, transition metal‐catalyzed direct (hetero)arylation reactions of heteroarenes with (hetero)aryl halides and pseudohalides have received significant attention as eco‐friendly and economic alternatives to classical methods for the construction of heteroaryl‐(hetero)aryl C C bonds by transition metal‐catalyzed cross‐couplings involving the use of stoichiometric amounts of organometallic reagents. This critical review with 430 references covers the results obtained in the period January 2009 to February 2013 in the area of the transition metal‐catalyzed direct inter‐ and intramolecular (hetero)arylation reactions of heteroarenes containing one heteroatom. Particular attention has been given to illustrate chemo‐ and site selectivity aspects of these reactions as well applications of these C C bond forming reactions in the synthesis of pharmaceutically relevant compounds, natural products and their analogues and precursors. The most recent advancements into the mechanism(s) of these reactions have also been briefly reported.

     

User‐Friendly [(Diglyme)NiBr2]‐Catalyzed Direct Alkylations of Heteroarenes with Unactivated Alkyl Halides through C?H Bond Cleavages

A nitrogen and phosphorus ligand‐free catalytic system derived from inexpensive [(diglyme)NiBr₂] allowed for efficient direct C H bond alkylations of heteroarenes with unactivated β‐hydrogen‐containing alkyl halides under basic reaction conditions.     

Iridium(III)‐Catalyzed Direct C?H Sulfonamidation of 2‐Aryl‐1,2,3‐triazole N‐Oxides with Sulfonyl Azides

We have developed a method for the direct sulfonamidation of 2‐aryl‐1,2,3‐triazole N‐oxides using sulfonyl azides as the amino source to release molecular nitrogen as the sole by‐product. This protocol exhibits excellent functional group tolerance and proceeds efficiently under external oxidant‐free conditions. Various 2‐(2‐sulfonamidoaryl)‐1,2,3‐triazoles were prepared in up to 97% yields for 25 examples with excellent regioselectivity.

     

Design and Synthesis of 2‐Methyl‐7‐aminobenzoxazole as Auxiliary in the Palladium(II)‐Catalyzed Arylation of a beta‐Positioned C(sp3)?H Bond

A palladium(II)‐catalyzed direct arylation of methylene C(sp³) H bonds by 2‐methyl‐7‐aminobenzoxazole as an effective auxiliary is reported. This process exhibited high beta‐site selectivity, broad substrate scope, and compatibility with different functional groups with moderate to high yields up to 89%.

     

Rhodium‐Catalyzed N‐tert‐Butoxycarbonyl (Boc) Amination by Directed C?H Bond Activation

N‐tert‐Butoxycarbonyl azide (BocN₃) was shown to be an efficient and economic source for the directed introduction of N‐Boc protected amino groups into the thiophene and benzene nucleus. Yields for the amination of 2‐pyridin‐2‐ylthiophenes (10 examples) were 52–88%. For the amination of the respective benzenes (10 examples) yields between 54% and 99% were recorded with an improved reactivity observed for substrates that bear an electron‐withdrawing group. The reaction was applied to short total syntheses of the indoloquinoline alkaloids quindoline and cryptolepine. The facile removal of the Boc protecting group was the key to the success of the syntheses. The scope of the reaction was extended to a C(sp³) H bond amination and to the amination of 2‐phenyloxazoline. For the amination of 2‐pyridin‐2‐ylbenzene a kinetic deuterium isotope effect of 2.0 was determined.

     

Synthesis of 3‐Aryl‐1‐trifluoromethyltetrahydroisoquinolines by Brønsted Acid‐Catalyzed C(sp3)?H Bond Functionalization

A concise route to 3‐aryl‐1‐trifluoromethyltetrahydroisoquinolines by a benzylic [1,5]‐hydride shift‐mediated C H bond functionalization was developed. The [1,5]‐hydride shift of the benzylic C(sp³) H bond to the trifluoromethylketimine derived from para‐anisidine occurred smoothly to produce cis‐1‐trifluoromethyl‐3‐aryltetrahydroisoquinolines in good to excellent chemical yields with good diastereoselectivities. In contrast, use of the N H ketimine furnished N‐unprotected tetrahydroisoquinolines in good yields in favor of the trans‐isomer.

     

High‐Valent Pentamethylcyclopentadienylcobalt(III) or ‐iridium(III)‐Catalyzed C?H Annulation with Alkynes: Synthesis of Heterocyclic Quaternary Ammonium Salts

Nine types of diversely fused heterocyclic quaternary ammonium salts were constructed through an oxidative C H annulation reaction. Both high‐valent pentamethylcyclopentadienylcobalt(III) and pentamethylcyclopentadienyliridium(III) were found to be effective as catalyst for this reaction. Broad substrate scope and good functional group tolerance were observed.

     

Acylperoxycoumarins as ortho‐C?H Acylating Agent via a Palladium(II)‐Catalyzed Redox‐Neutral Process

An unprecedented palladium(II)‐catalyzed biomimetic aliphatic acyl (‐COR) group transfer was observed from acyl‐α‐peroxycoumarins to the ortho C H sites of directing arenes. Here, the C H activation is associated with a concomitant acyl group transfer via a Pd(II)‐catalyzed, redox‐neutral process. While methods for ortho aroylation (‐COAr) are well documented ortho acylation (‐COR) processes are scarce, hence the present redox‐neutral method is most ideal for o‐acylation of directing substrates.

     

“On Water” Direct and Site‐Selective Pd‐Catalysed C?H Arylation of (NH)‐Indoles

This communication describes the development of a versatile catalytic system based on palladium(II) acetate/bis(diphenylphosphino)methane [Pd(OAc)₂/dppm] that works “on water” giving site‐selective C H arylation of (NH)‐indoles without protecting or directing groups. Remarkably, the control of regioselectivity was achieved by small changes in the “extra‐catalytic” base/halide partners. These innovative methodologies allow a high‐yielding access to both C2 and C3‐arylindoles, as well as 2,3‐diarylindoles, and display high chemo/regioselectivities and structural versatility with regard to either indole or aryl moieties.     

Rhodium(III)‐Catalyzed C(sp2)?H Activation and Electrophilic Amidation with N‐Fluorobenzenesulfonimide

An electrophilic amidation via a cationic rhodium(III)‐catalyzed C(sp²) H activation has been developed with the commercially available N‐fluorobenzenesulfonimide as the amino source under external oxidant‐free conditions. This amidation requires only a catalytic amount of base and exhibits excellent functional group tolerance and regioselectivity, providing a new avenue in direct C(sp²) H amidation.     

中国塑料工业(2010)

介绍了2010年我国塑料工业的发展状况,包括各种塑料制品产销量、产值及进出口情况、合成树脂产销量及进出口情况、塑料机械产销量及进出口状况、塑料助剂的产销量等;同时还指出了我国塑料工业存在的问题,对我国塑料工业在十二.五期间的发展提出了一些建议。     

DDQ‐mediated Direct C(sp3)?H Cyanation of Benzyl Ethers and 1,3‐Diarylpropenes under Solvent‐ and Metal‐free Conditions

A direct cyanation of benzyl ethers and 1,3‐diarylpropenes with TMSCN was performed under solvent‐ and metal‐free conditions. This oxidative cross dehydrative coupling (CDC) reaction was promoted by 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone (DDQ) and provided rapid access to a broad range of nitriles in good to excellent yields.

     

Silver(I)‐Mediated C?H Amination of 2‐Alkenylanilines: Unique Solvent‐Dependent Migratory Aptitude

A highly effective silver(I)‐mediated C H amination of 2‐alkenylanilines has been developed to afford a diverse range of substituted indoles. High functional group tolerance, broad substrate scope, simple/fast/high‐yielding reaction, and recovery/reuse of the inexpensive silver oxidant are noteworthy. Furthermore, an uncommon migratory process of β‐monosubstituted 2‐alkenylanilines with solvent‐dependence was demonstrated.

     

Copper‐Catalyzed Direct C?H Arylation of Thieno[3,4‐c]pyrrole‐4,6‐dione (TPD): Toward Efficient and Low‐Cost Synthesis of π‐Functional Small Molecules

A series of thieno[3,4‐c]pyrrole‐4,6‐dione (TPD)‐based functional small molecules were efficiently synthesized through direct C H arylations using inexpensive copper salts. In this study, we examined all required reaction parameters including various copper complexes, ligands, bases, and (co)solvents. Under the optimum reaction conditions, the C H arylation proceeded smoothly and a variety of functional groups such as ester, nitrile, fluoride, chloride, triazene, and amine were tolerated. This method provides a step‐economical and relatively low‐cost synthetic alternative to presently used coupling reactions for the preparation of TPD‐containing π‐functional materials.

     

COOH?MWCNTs‐induced BiFeO3‐poly(vinylidene fluoride) (PVDF) composites with enhanced dielectric and ferroelectric properties

In this work, flexible three phase composite films were prepared with surface functionalized multi‐walled carbon nanotubes (f‐MWCNTs) and bismuth ferrite (BiFeO₃;BFO) particles embedded into the poly(vinylidene fluoride) (PVDF) matrix via solution casting technique. The properties and the microstructure of prepared composites were investigated using an impedance analyzer and field emission scanning electron microscope. The micro‐structural study showed that the f‐MWCNTs and BFO particles were dispersed homogeneously within the PVDF matrix, nicely seated on the floor of the f‐MWCNTs separately. The dielectric measurement result shows that the resultant composites with excellent dielectric constant (≈96) and relatively lower dielectric loss (<0.23 at 100 Hz). Furthermore, the percolation theory is explored to explain the dielectric properties of the resultant composites. It says that the percolation threshold of f_MWCNTs = 0.9 wt % and the enhancement of the dielectric constant of the composite was also discussed. In addition, the remnant polarization of the un‐poled PVDF‐BFO‐f‐MWCNTs composites (2P_r ～1.34 µC/cm² for 1.1 wt % of f‐MWCNTs) is also improved. These three phase composites provide a new insight to fabricate flexible and enhanced dielectric properties as a promising application in modern electrical and electronic devices. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46002.     

Palladium(II)‐Catalyzed Direct ortho‐C?H Acylation of Anilides by Oxidative Cross‐Coupling with Aldehydes using tert‐Butyl Hydroperoxide as Oxidant

An efficient palladium‐catalyzed C H acylation with aldehydes using tert‐butyl hydroperoxide (TBHP) transforms various anilides into synthetically useful 2‐aminobenzophenone derivatives under mild conditions (40 °C, 3 h). The acylation reaction exhibits excellent regioselectivity and functional group tolerance, and simple aromatic aldehydes, functionalized aliphatic aldehydes and heteroaromatic aldehydes are effective coupling partners. The acylation reaction is probably initiated by a rate‐limiting electrophilic C H cyclopalladation (k_H/k_D=3.6; ρ⁺=−0.74) to form an arylpalladium complex, followed by acyl radical functionalization.