Aromatic Alkynes Research Articles

A copper-catalyzed multicomponent reaction for the synthesis of thioamide skeletons

In this report, in situ generated sulfide has been reacted with sulfonylketimine derived from the reaction of alkynes and sulfonyl azides by the action of copper salts to form a wide range of thioamide derivatives. Various terminal alkynes including aromatic, heteroaromatic, and aliphatic alkynes have been well tolerated and the reaction also shows good generality along with azides.

Transformation of Alkynes into α- or β-Difluorinated Alkyl Azides by an Efficient One-Pot Two-Step Procedure.

Reported herein an unprecedented 1,2-azide migratory hydroazidation and subsequent gem-difluorination of alkynes accessing β-difluorinated alkyl azides. Importantly, functional group controlled 1,2-azide or 1,2-aryl migration was observed in the case of aromatic alkynes. Moreover, the azide group is sustained up to the final product. The method can be easily adapted for large-scale preparation, and the resulting products can be readily transformed into gem-difluoro group containing amine and triazole derivatives.

Multicomponent Tandem Polymerization of Aromatic Alkynes, Carbonyl Chloride, and Fischer's Base toward Poly(diene merocyanine)s

Summary of main observation and conclusionMulticomponent polymerization (MCP) is a popular tool to construct polymers with diverse structure, simple operation, and high efficiency, which faces the challenges of limited product structures. Multicomponent tandem polymerization (MCTP), combining two or multiple reactions in a one‐pot fashion, could expand the scope of MCP and enrich the polymer structures. Herein, a one‐pot three‐component tandem polymerization of diynes, carbonyl chloride, and Fischer's base has been developed to afford conjugated poly(diene merocyanine)s with mild condition, satisfactory molecular weights (Mw up to 10900 g/mol) and yields (up to 81%). The polymers enjoy good solubility and high thermal stability. The unique emission behavior of the model compound and polymer show that they are aggregation‐induced emission (AIE)‐active, suggesting that the diene merocyanine moiety is a potential AIEgen. This MCTP shows great potential in the preparation of functional polymer materials, which could build new AIE functional units directly from the polymerization, demonstrating its synthetic simplicity and elegance.

A heterogeneous catalytic and solvent-free approach to 1,2-dihydroquinoline derivatives from aromatic amines and alkynes by tandem hydroarylation-hydroamination

This study describes a mesoporous aluminosilicate (ASM) catalyst-induced one-step synthesis of substituted dihydroquinolines through a hydroarylation/hydroamination cascade reaction under solvent-free conditions. A sol-gel method was utilized to prepare the ASM catalyst using tetraethyl orthosilicate (TEOS) and aluminum nitrate (Al(NO3)3.9H2O). The catalytic protocol, utilizing simple starting materials and a heterogeneous catalyst in a clean reaction environment, is considered an alternative and economically viable route to synthesize a wide range of 1,2-dihydroquinoline derivatives.

Copper Aluminate Spinel in Click Chemistry: An Efficient Heterogeneous Nanocatalyst for the Highly Regioselective Synthesis of Triazoles in Water

An expeditious protocol for the one-pot synthesis of 1,4-disubstituted (β-hydroxy)-1,2,3-triazoles in an aqueous medium has been developed using copper aluminate nanoparticles. This heterogeneous catalytic system was found to drive a multicomponent click reaction between organic azides (generated in situ from epoxides or halides) and terminal aliphatic or aromatic alkynes in up to 96% yield without the need for a reducing agent. Structurally diverse 1,2,3-triazoles were synthesized in good to excellent yields, and the catalyst could be easily separated by simple filtration, recycled, and reused in six subsequent cycles.

Cover Feature: Enhancing Ligand‐Free Fe‐Catalyzed Aminocarbonylation of Alkynes by ZrF4 (ChemCatChem 21/2019)

The Cover Feature illustrates ligand-free Fe-catalyzed aminocarbonylation of alkynes by ZrF4. In their Communication, Z. Huang et al. demonstrated the utility of readily prepared ZrF4 in transforming various aromatic and aliphatic alkynes into the desired α,β-unsaturated amides in good to excellent yields. Preliminary mechanistic studies by in-situ NMR experiments provided insights into the catalytic role of ZrF4 through F⋅⋅⋅H-N hydrogen bonding and activation of Fe3(CO)12. More information can be found in the Communication by Z. Huang et al. on page 5236 in Issue 21, 2019 (DOI: 10.1002/cctc.201900995).

MnCl2‐Mediated Carbonylative Sonogashira Coupling of Aryl Iodides and Aromatic Terminal Alkynes by Using CO

AbstractA new, simple, and efficient synthetic protocol has been developed for Carbonylative Sonogashira Coupling (CSC) with aryl iodides, aromatic terminal alkynes, and CO (2 atm) by using manganese chloride (MnCl2) as a catalyst. This method has shown a good‐to‐excellent yield of the desired products. Additionally, it was found to have ensured the synthesis of 2‐substituted flavones.

Palladium-catalyzed methylation of terminal alkynes

In this communication, a palladium-catalyzed procedure for the methylation of terminal alkynes has been developed. With N,N,N-trimethylbenzenaminium trifluoromethanesulfonate as the methyl source, various desired products were obtained in moderate to good yields. Both aromatic and aliphatic alkynes are applicable.

Aminoalkylation of [1.1.1]Propellane Enables Direct Access to High-Value 3-Alkylbicyclo[1.1.1]pentan-1-amines.

Bicyclo[1.1.1]pentanes are effective bioisoteres for aromatic rings, tert-butyl groups, and alkynes. Here we report the first method to synthesize 3-alkylbicyclo[1.1.1]pentan-1-amines directly from [1.1.1]propellane via sequential addition of magnesium amides and alkyl electrophiles. The mild reaction conditions tolerate a variety of important functional groups and enable efficient incorporation of several pharmaceutically relevant amines onto the bicyclo[1.1.1]pentane scaffold. This method's utility is highlighted by its ability to significantly streamline the syntheses of several important bicyclo[1.1.1]pentan-1-amine building blocks.

Synthesis and Functionalization of Ynone-Based Tubular Microporous Polymer Networks and Their Carbonized Products for CO2 Capture

Ynone-based microporous polymer networks (YMPNs) were synthesized by the reaction of aromatic dicarboxylic acid chloride and alkyne groups under Sono-gashira cross-coupling reaction conditions. As the reaction proceeded in a mixture of toluene and triethylamine (TEA), tubular precipitates formed rapidly. The microscopic and XRD studies showed thatthe precipitates had a core-shell structure with a rod-shaped triethylammonium chloride (TEA-HC1) crystalline core and a polymeric shell. The core was removed by washing with methanol to provide a hollow polymeric tube. The TEA-HC1 rod formed in situ during the cross-coupling reaction and served as a template in forming the tubular morphology. YMPNs could be modified with ease because of the presence of highly reactive ynone groups. YMPNs were functionalized with ethylenediamine by the Michael-type addition reaction. The amino group functionalized YMPNs were used as precursors of nitrogen-doped porous carbons. The pyrolysis of the polymers at 800 °C produced microporous carbon materials withoutthe activation process. The carbon materials showed significantly enhanced Brunauer-Emmett-Teller (BET) surface areas and CO2 uptake capacities compared to their precursor polymers.

Fiber-supported Pd Catalysts for Cross-coupling Reaction of Aromatic and Aliphatic Terminal Alkynes

Increasing the efficiency of cross-coupling reaction under mild condition and easy catalyst separation is a key issue in the realistically chemical industry application. Here, we report that the fiber-supported Pd catalyst shows a high activity and selectivity for the cross-coupling reaction of terminal alkynes. The yield of the asymmetric 1,3-diyne can reach 83% at 80 °C and 4 h reaction time in N,N-dimethylacetamide (DMAc), and about 87% selectivity. XPS, EDS and SEM results show that Pd metal ions are successfully loaded onto the fiber surface and are reduced to produce active component of Pd (0) by terminal alkyne in reaction. We consider that Pd (0) is the active center of the catalytic cycle, the coordination of the fibers can stabilize Pd particles on the supports and increases the catalytic activity of Pd catalysts. Cu (I) plays a synergistic catalytic role. This study provides an alternative pathway for the high efficient cross-coupling reaction.

Synthesis of Benzofulvenes via Cp*Co(III)-Catalyzed C–H Activation and Carbocyclization of Aromatic Ketones with Internal Alkynes

A highly efficient and practical synthesis of benzofulvenes was developed via ketone-directed Cp*Co(III)-catalyzed sequential C-H activation, addition, cyclization, and dehydration cascade processes between simple aromatic ketones and alkynes. The reaction tolerates a variety of functional groups, and various benzofulvenes were efficiently synthesized in 42-92% yields.

Palladium(II)‐Catalyzed Intermolecular Cascade Cyclization of Methylenecyclopropanes with Aromatic Alkynes: Construction of Spirocyclic Compounds Containing Indene and 1,2‐Dihydronaphthalene Moieties

AbstractA palladium(II)‐catalyzed intermolecular cascade cyclization of methylenecyclopropanes with aromatic alkynes is reported in this paper. The reaction involves a migratory insertion of alkyne, an intramolecular Heck‐type reaction, and β‐H elimination, providing a series of spirocyclic compounds containing indene and 1,2‐dihydronaphthalene moieties in moderate to excellent yields upon heating.magnified image

Anti-Markovnikov stereoselective hydroamination and hydrothiolation of (hetero)aromatic alkynes using a metal-free cyclic trimeric phosphazene base

Hydroamination and hydrothiolation are the most efficient and completely atom-economical process to construct important enamine and vinyl sulfide intermediates in pharmaceutical and organic chemistry. The cyclic trimeric phosphazene base (CTPB) showed great catalytic activity for the anti-Markovnikov stereoselective hydroamination and hydrothiolation of alkynes in good to excellent yields. A broad substrate scope of alkynes and nucleophiles was demonstrated, including aryl and heteroaryl alkynes, terminal and internal alkynes, different N-heterocycles, thiols and thiophenols. This versatile and cost-efficient approach with good stereoselectivity and excellent functional group tolerance provided new opportunity for the organocatalyzed hydrofunctionalization of alkynes.

Direct Construction of Acid-Responsive Poly(indolone)s through Multicomponent Tandem Polymerizations.

Multicomponent polymerizations (MCPs) as a burgeoning field in polymer chemistry has proved to be a powerful and popular tool for the synthesis of functional polymer materials with diverse and complex structures. To explore the general applicability of MCPs and enrich the product structures of MCPs, multicomponent tandem polymerizations (MCTPs) with great synthetic simplicity and efficiency were pursued. In this work, MCTPs of N-(2-iodophenyl)-3-phenyl-N-tosylpropiolamide, aromatic terminal alkynes, and diamines were explored through combining Sonogashira coupling and Michael addition reaction in a one-pot procedure. The MCTPs could proceed efficiently and conveniently under mild conditions with Pd(PPh3)2Cl2, CuI, and i-Pr2NEt, affording 12 poly(indolone)s with unique structures and high Mws (up to 30400 g/mol) in high yields (up to 97%). The poly(indolone)s possess a unique acid-triggered fluorescence "turn-on" response which could realize specific detection of CF3SO3H from other inorganic and organic acids through a rapid acid-catalyzed reaction from enamine to ketone.

Synthesis and systemic toxicity assessment of quinine-triazole scaffold with antiprotozoal potency

A series of hybrid antiprotozoal compounds with quinine-triazolyl scaffold were prepared by copper catalyzed Huisgen 1,3-dipolar cycloaddition via O-mesylation with mesyl chloride followed by azide displacement. The synthesized azide derivative was made to react with various aromatic and aliphatic alkynes. The triazolyl-linked quinine scaffolds were synthesized under solvent-free mechanochemical ball milling conditions. Products (6a-s) were screened for in-vitro antimalarial and antileishmanial activity. Screening results indicated that out of the synthesized series of 19 products, compounds 6d, 6h, 6l, 6m, and 6n showed significant antimalarial (P. falciparum) and antileishmanial activities (L. donavani) with IC50 values 0.28, 0.28, 0.25, 0.33, 0.76 µM and 8.26, 4.4, 1.78, 3.95, and 4.06 µM, respectively. Further toxicological analysis established the Median lethal dose (LD50), No observed adverse effect level (NOAEL) and human equivalent dose (HED) of the most potent compounds by acute and sub acute toxicity studies performed in rodent animal model. The studies revealed that compounds (6d, 6h, 6l and 6m) did not reveal any toxic manifestation at dose 1000 mg/Kg and from which the corresponding HED was calculated to be 13.84 mg/kg.

Preparation of Ethynylbenzene Derivatives from Substituted Benzaldehydes

We have tested a number of synthetic methods for large-scale synthesis of targeted substituted aromatic alkyne (S)-[4-(3-chloro-5-ethynyl-4-fluoro-phenyl)-1-methyl-butyl]-carbamic acid benzyl ester (1). This research resulted in an improved method for the Corey–Fuchs approach to alkyne synthesis from aldehydes. Importantly, we have shown that the use of P(OCH3)3/CBr4 in toluene for the synthesis of the dibromo-methylene intermediate (S)-{4-[3-chloro-5-(2,2-dibromo-vinyl)-4-fluoro-phenyl]-1-methyl-butyl}-carbamic acid benzyl ester (5) allows the synthesis of alkyne 1 under conditions that may be amenable for scaling-up. Since this method was developed, multiple batches of alkyne 1, each approaching 100 g in size, have been prepared under process-friendly conditions, as well as multigram batches of other alkynes.

Copper (II) catalyzed homocoupling and heterocoupling of terminal alkynes

Cu(OTf)2 catalyzed homo– and heterocoupling of aromatic and aliphatic terminal alkynes has been developed. Symmetric and unsymmetric 1,3-diynes have been synthesized in good yields under an aerobic condition in the presence of an organic base DBU. This reaction features mild conditions, a wide substrate scope, and excellent functional group compatibility.

Functionalized graphene oxide anchored to Ni complex as an effective recyclable heterogeneous catalyst for Sonogashira coupling reactions

The Sonogashira cross coupling reaction is an applied method for preparation of diarylethyne compounds from readily available aryl halide derivatives and phenyl acetylene. The coupling reaction using nickel complex of N,N′-Bis(2-hydroxyethyl)ethylenediamine onto core shell graphene oxide (GO@SiO2-BHED-Ni) as a catalyst was studied in this research. This heterogonous catalyst showed good thermal stability, highly efficiency and recyclability in the reaction. Moreover, the catalyst is simply separated and can be reused several times without significant loss of catalytic activity. A wide range of aryl halides was coupled successfully under palladium and phosphine free conditions. The use of this catalyst led to the formation of substituted aromatic alkynes in excellent yields and short reaction times.

Direct Transformation of Terminal Alkynes into Amidines by a Silver-Catalyzed Four-Component Reaction.

An unprecedented conversion of terminal alkynes into N-sulfonimidamides (amidines) is reported by a silver-catalyzed, one-pot, four-component reaction with TMSN3, sodium sulfinate, and sulfonyl azide. The reaction scope includes both aromatic and aliphatic alkynes. A possible cascade reaction mechanism, consisting of alkyne hydroazidation, sulfonyl radical addition, 1,3-dipolar cycloaddition by TMSN3, and retro-1,3-dipolar cycloaddition, is proposed. TMSN3 is found to play an essential role in each step of the reaction.