Refernces
10.1016/j.tet.2015.10.002
The study presents a facile and general method for synthesizing 2,5,7-trisubstituted indoles, which are significant in pharmaceuticals and natural compounds due to their biological activity. The researchers utilized a one-pot Sonogashira cross-coupling reaction followed by a palladium-catalyzed cyclization to construct the indole rings from readily available 2-bromo-6-iodo-4-substituted and 2-bromo-4-chloro-6-iodoanilines. Further functionalization at the C7 and C5 positions was achieved through alkynylations, Suzuki-Miyaura cross-couplings, and Buchwald-Hartwig C-N bond forming reactions. The methodology offers high yields, simplicity, and versatility, making it valuable for the synthesis of biologically active compounds. The study also includes one-pot protocols for the synthesis of these complex indole derivatives, enhancing the efficiency of the process.
10.1016/j.tetlet.2020.151775
The research presents a transition-metal-free approach for the synthesis of 1,3-diynes and related molecules through Glaser- and Cadiot-Chodkiewicz-type coupling reactions. The study utilizes terminal alkynes or 1,1-dibromo-1-alkenes as reactants and explores the efficiency of molecular iodine as a catalyst in aqueous medium to achieve the desired 1,3-diynes in moderate to good yields. Terminal alkynes (such as phenylacetylene) as starting materials for the synthesis of 1,3-diynes. Piperidine as a base in the reactions. The reaction conditions demonstrate a significant functional group tolerance in water, and the scope of the metal-free method for synthesizing 1,3-enynes has been investigated. The research also includes control experiments to establish a plausible reaction mechanism, which is further supported by gas chromatography-mass spectrometry (GC-MS) analysis. The findings reveal that the process likely involves a radical pathway and is influenced by the presence of aerial oxygen. The study is significant as it offers an eco-friendly and cost-effective method for C-C bond forming reactions, which are essential in the synthesis of complex molecules for pharmaceuticals, materials science, and other applications.
10.1016/j.tetlet.2005.11.001
The research discusses the investigation of a heterogeneous intermolecular hydroamination reaction between terminal alkynes and aromatic amines using inexpensive transition metal-exchanged clay catalysts. The study focuses on the synthesis of aromatic imines, which are important for producing nitrogen-containing compounds. The experiments involved various metal-exchanged montmorillonite K-10 catalysts, with Cu2+ showing the highest yield in the hydroamination of phenylacetylene with p-toluidine. The reaction was found to be highly regioselective, yielding only Markovnikov addition products. The reactivity of different alkynes and aniline derivatives was evaluated, with aromatic alkynes and electron-donating substituents on anilines showing better yields. The analyses used to determine yields and product selectivity included gas chromatography (GC), nuclear magnetic resonance (NMR), Fourier-transform infrared spectroscopy (FT IR), and gas chromatography-mass spectrometry (GCMS).
10.1016/j.tetasy.2009.12.002
The research focuses on the synthesis of 4,4'-biquinazoline alcohols, which are chiral catalysts used in the enantioselective alkynylation of aldehydes with phenyl acetylene. The study outlines a series of chemical reactions beginning with the condensation of (S)-2-acetoxycarboxylic acid chlorides and 2-aminobenzamide, followed by key steps such as chlorination, nickel(0)-mediated homocoupling, and deprotection to yield the desired chiral 4,4'-biquinazoline alcohols. These catalysts are then combined with Ti(OiPr)4 and utilized in the asymmetric addition of zinc acetylide, generated in situ from phenylacetylene and diethylzinc, to aldehydes. The experiments involved various reactants, including SOCl2, anthranilamide, NaOH, TBDMSCl, POCl3, PhNEt2, NiCl2?6H2O, Zn, DMF, and Bu4NF, among others. The analyses used to characterize the compounds and determine their enantiomeric purities included HPLC, NMR spectroscopy, IR spectroscopy, X-ray diffraction, and specific rotation measurements. The best enantiomeric excess achieved in this study was 75%.
10.1021/om800119f
The study investigates the synthesis, reactions, and catalytic properties of diphosphinidenecyclobutene ruthenium complexes, specifically focusing on [RuCl(μ-Cl)(CO)(DPCB-OMe)]2 (1a) and its hydrido derivative [RuH(μ-Cl)(CO)(DPCB-OMe)]2 (2a). These complexes serve as highly efficient catalysts for the Z-selective hydrosilylation of terminal alkynes, such as phenylacetylene. The researchers explored the reduction process of 1a to 2a using water and HSiMe2Ph, identifying key intermediates like the aqua complex [RuCl2(CO)(H2O)(DPCB-OMe)] (8a) and the hydroxy complex [Ru(OH)(μ-Cl)(CO)(DPCB-OMe)]2 (9a). The study also delved into the reactivity of 2a towards phenylacetylene and HSiMe2Ph, revealing that the resulting styryl complex [Ru(CHdCHPh)Cl(CO)(DPCB-OMe)] (3a) can smoothly react with HSiMe2Ph even at low temperatures, leading to the formation of (Z)-styrylsilane. The high catalytic efficiency of the DPCB-OMe complexes is attributed to their structural features, which provide ample space for hydrosilane association and facilitate the metathesis between Ru-C and H-Si bonds, combined with the strong π-accepting ability of the DPCB-OMe ligand.
10.1246/bcsj.72.163
The study investigates the solvolysis reactions of phenyl[(E)-styryljiodonium tetrafluoroborate (1) in various solvents, focusing on the products, reaction rates, and mechanisms involved. The primary chemicals used are phenyl[(E)-styryljiodonium tetrafluoroborate as the substrate, and different solvents including methanol, ethanol, 2,2,2-trifluoroethanol (TFE), and acetic acid. The study also employs labeled substrates, such as the α-deuterated substrate (1-αD), to analyze the reaction mechanisms. The reactions involve α-elimination and substitutions with configurational retention and inversion. In methanol and ethanol, α-elimination is the main reaction, producing phenylacetylene (3) as the major product, while substitution reactions become more significant in less basic solvents like acetic acid and TFE. The study finds that the reaction rates and the fraction of α-elimination decrease as the solvent basicity decreases. The substitution mechanism is concluded to involve parallel pathways: an SN1-type with a vinylenebenzenium ion intermediate leading to retention and a vinylic SN2-type with a direct attack by the nucleophilic solvent leading to inversion.
10.1021/om020686z
The research investigates the synthesis and reactivity of silyl(boryl)platinum(II) complexes, which are assumed to be key intermediates in catalytic silylborylation of alkynes and alkenes but have not been previously observed. The study aims to provide a detailed understanding of the catalytic cycle for silylborylation by synthesizing these complexes and examining their reactions stepwise. The researchers prepared four types of silyl(boryl)platinum(II) complexes (2a-2d) through oxidative addition of silylboranes to platinum(0) complexes, using tertiary phosphine ligands such as PMe3, PMe2Ph, and PEt3. These complexes were characterized by NMR spectroscopy and elemental analysis. The study found that complexes 2a-2c undergo selective insertion of phenylacetylene into the Pt-B bond at room temperature, forming insertion complexes 3a-3c, while 2d remains inactive. The reactivity of these insertion complexes decreases in the order 3c > 3b > 3a. The researchers also determined the X-ray structure of 3b and conducted kinetic studies on the insertion mechanism, revealing that the process involves prior dissociation of the phosphine ligand, followed by insertion of phenylacetylene into the Pt-B bond. The study concludes that the type of tertiary phosphine ligand significantly affects the reactivity of these complexes, providing insights into the catalytic silylborylation process and highlighting the importance of ligand choice in controlling reaction outcomes.
10.1016/j.jorganchem.2008.04.006
The study focuses on the synthesis, characterization, and reactivity of rhodium(III) complexes with N-boranyl-1,3,5-triaza-7-phosphaadamantane (N–B–PTA(BH3)) ligands. The reaction of N–B–PTA(BH3) with [CpRhCl(l-Cl)]2 yields complexes [CpRh{N–B–PTA(BH3)}Cl2] (3) or [CpRh{N–B–PTA(BH3)}2Cl]Cl (5), containing one or two P-bonded boronated PTA ligands. The hydride [CpRh{N–B–PTA(BH3)}H2] (8) was also obtained by reaction with NaBH4. These complexes can undergo hydrolysis to produce dihydrogen and H3BO3, along with PTA derivatives. Furthermore, the reaction of complex 8 with electron-poor alkynes results in the formation of alkene complexes [Cp*Rh{N–B–PTA(BH3)}(g2-CH2 = CHR)] without affecting the N–BH3 moiety. The X-ray crystal structures of complexes 3 and 10 were determined and discussed, providing insights into the coordination chemistry and potential applications of these water-soluble rhodium complexes.
10.1021/jo102060j
The study presents an efficient method for synthesizing iodoisoquinoline-fused benzimidazole derivatives, which are significant for their potential biological activities such as anti-HIV-1, anticancer, antimicrobial, and antifungal properties. The researchers developed a tandem cyclization strategy using CuI/I2 to promote the electrophilic tandem cyclization of 2-ethynylbenzaldehydes with ortho-benzenediamines. This approach led to the formation of the desired iodoisoquinoline-fused benzimidazoles in moderate to good yields. The study also explored the scope of the reaction with various substrates and demonstrated the potential of the synthesized products for further functionalization through cross-coupling reactions, highlighting the importance of this method for drug discovery and the development of heterocyclic compounds with diverse biological activities.
10.1039/c2dt30448a
The research focuses on the utilization of a bifunctional frustrated Lewis pair (FLP), specifically 1-[bis(pentafluorophenyl)boryl]-3,5-di-tert-butyl-1H-pyrazole (1), for the fixation of carbon dioxide (CO2) and related small molecules. The study explores the reactivity of this FLP with CO2, paraformaldehyde, tert-butyl isocyanate, tert-butyl isothiocyanate, methyl isothiocyanate, benzonitrile, and phenylacetylene, resulting in the formation of zwitterionic, bicyclic boraheterocycles (adducts 3–8) and other complexes (adducts 9 and 10). The experiments involved treating the FLP with these reactants in toluene solutions, followed by stirring, solvent evaporation, and in some cases, washing with pentane to isolate the products. The molecular structures of the products were established using X-ray diffraction analyses, and Density Functional Theory (DFT) calculations at the M06-2X/6-311++G(d,p) level of theory were performed to understand the energetics of the CO2 fixation process. The analyses included NMR (1H, 13C, 11B, and 19F), IR spectroscopy, and elemental analysis to characterize the products and confirm the fixation of the small molecules.
10.1016/S0022-328X(01)00807-5
This study investigates the reaction of tetrakis[di-tert-butyl(methyl)silyl]-2-disilagermirene (1b) with phenylacetylene to synthesize a novel metalladiene, specifically 1,1,2,3-tetrakis[di-tert-butyl(methyl)silyl]-4-phenyl-1,2-disila-3-germacyclopenta-2,4-diene (2b). The reaction produced bright orange crystals of 2b, which features a Si–Ge double bond and a C–C double bond, marking it as a previously unreported compound. The study utilized tetrakis[di-tert-butyl(methyl)silyl]-1-disilagermirene (1a) as an isomer of 1b and phenylacetylene as a reactant to explore the synthesis and reactivity of these compounds. The purpose of using these chemicals was to investigate the formation mechanisms, structural characteristics, and potential conjugation effects of the resulting metalladiene, contributing to the understanding of Group 14 element chemistry.
10.1039/b209165h
The purpose of this study was to identify compounds that could specifically inhibit the mammalian squalene epoxidase, potentially leading to therapeutic applications in managing cholesterol levels. Through structure-activity relationship studies, the researchers discovered that compound 19, 1-[3-(3,5-dichlorophenyl)prop-2-ynyl]-3-methylpiperidine hydrochloride, exhibited an IC50 of 2.8 ± 0.6 μM against rat liver squalene epoxidase and was found to be inactive against fungal squalene epoxidase. The chemicals used in this process included a series of 3-phenylprop-2-ynylamines (compounds 1–54), various substituted phenylacetylenes, and amines, which were synthesized using techniques such as the Mannich reaction and Sonogashira reaction conditions.
10.1016/j.tetlet.2013.07.029
The study presents a copper-catalyzed one-pot synthesis of alkynyl imidates and alkynyl thioimidates through a coupling reaction involving terminal alkynes, trichloroimidates generated in situ from trichloroacetonitrile and benzyl alcohols or thiols. The key chemicals include phenylacetylene as a model terminal alkyne, trichloroacetonitrile as a precursor for trichloroimidates, and benzyl alcohol or thiol as the source of the imidate or thioimidate group. Copper iodide (CuI) acts as the catalyst, and triethylamine (Et3N) is used as a base. The reaction is optimized in acetonitrile at room temperature, yielding the desired products in good yields. The mechanism involves the formation of a copper acetylide intermediate, which reacts with the trichloroimidates to form a tetrahedral intermediate, followed by the elimination of CuCCl3 to produce the final products. This method offers a versatile and efficient route for synthesizing functionalized alkynes with readily available starting materials and catalysts.
10.1021/jo00805a002
The study investigates the reactions of 2-diazoacenaphthenone (1) with various olefins and acetylenes. The researchers found that 1 did not decompose in boiling benzene or toluene but underwent copper-catalyzed thermolysis in boiling toluene to form biacenedione. In boiling xylene, 1 produced biacenedione and a trace amount of acenaphthenequinone ketazine. When 1 reacted with olefins like ethyl acrylate, acrylonitrile, ethyl a-bromoacrylate, and methyl vinyl ketone in refluxing benzene, it yielded spiro[acenaphthenone-2,1'-cyclopropanes] (3a-d, 4a-c, 7) with two stereoisomers for some reactions. Reactions with acrolein, phenylacetylene, and diethyl acetylenedicarboxylate led to the formation of 2'-hydroxymethylspiro[acenaphthenone-2,1'-cyclopropanes] (5, 6) and spiro[acenaphthenone-2,3'(3'H)-pyrazoles] (9, 10). The study also explored the reaction of 1 with bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic anhydride, producing spiro[acenaphthenone-2,3'-tricyclooctanedicarboxylic anhydride] (8). The researchers used various analytical techniques to confirm the structures and properties of the synthesized compounds.
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