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.2004.09.136
The study focuses on the reactivity of substituted pyridinium N-(20-azinyl)aminides in the Suzuki–Miyaura cross-coupling reaction, a widely used method for forming sp2–sp2 carbon–carbon bonds. The researchers investigated the coupling of these compounds with various boronic acids, using Cs2CO3 as a base, which resulted in good yields and substitution on the negatively charged moiety. They optimized the reaction conditions and found that the process was efficient for a range of substrates, including those with electron-deficient diazine rings, albeit requiring longer reaction times. The study also explored a double Suzuki process with a dibromoaminide to yield diarylated ylides. The results provide a valuable strategy for the synthesis of functionalized 2-aminoazines, which are important in medicinal and heterocyclic chemistry, and the researchers are continuing their efforts to expand the application of this process to other N-aminides.
10.1016/j.inoche.2009.10.023
The research focuses on the synthesis and characterization of amino-salicylaldimine-palladium(II) complexes as efficient catalysts for Suzuki and Heck cross-coupling reactions, which are crucial for the synthesis of various organic compounds including natural products and pharmaceuticals. The study involves the preparation of these palladium complexes with different ligands, such as morpholine, piperidine, pyrrolidine, 4-methylpiperazin, and diisopropylamine, and their subsequent evaluation as catalysts under various reaction conditions. The complexes were characterized using techniques like IR spectrometry, 1H NMR, and elemental analysis, with the crystal structure of one complex confirmed by X-ray diffraction analysis. The effectiveness of these catalysts was tested in Suzuki reactions using 4-chlorobenzaldehyde with phenylboronic acid, optimizing the reaction conditions by varying solvents, bases, and temperatures. The Heck reaction was also explored with aryl bromides and different olefins. The study utilized GC-MS to determine the conversion yields of the reactions, providing a comprehensive analysis of the catalytic activities and the influence of electronic and steric factors on the reaction outcomes.
10.1016/j.jorganchem.2008.02.017
The study focuses on the synthesis and application of imidazolium salicylaldimine frameworks as tridentate N-heterocyclic carbene (NHC) ligands for the preparation of Pd(II) complexes. These ligands were designed to control the stability of active species and improve catalytic activity in various chemical transformations. The researchers synthesized sterically hindered salicylaldimine functionalized imidazolium salts and characterized them using spectroscopic techniques. They then reacted these salts with Pd(OAc)2 to form Pd(II) complexes, which were further characterized and tested for their efficiency in the Suzuki–Miyaura reaction, a method for C–C bond formation. The study found that these complexes were effective catalysts, particularly when activated arylbromides were used as substrates. The chemicals used in the study included salicylaldimine, imidazolium salts, arylmethyl-N chain components (such as phenyl, 2,4,6-trimethylphenyl, and 2,3,4,5,6-pentamethylphenyl), Pd(OAc)2, and phenylboronic acid, among others. These chemicals served the purpose of creating new tridentate Pd(II) complexes and evaluating their catalytic performance in the Suzuki–Miyaura reaction.
10.1016/S0040-4039(00)95184-0
The research focuses on the regiospecific total synthesis of ellipticine, a 6H-pyrido[4,3-b]carbazole alkaloid with significant anticancer activity. The purpose of the study was to develop a general synthetic approach that would allow for the preparation of a number of ellipticine derivatives. The researchers achieved this by employing a versatile coupling reaction between phenylboronic acid and a substituted bromoisoquinoline, followed by carbazole ring formation via a nitrene insertion reaction. This method successfully yielded ellipticine, and the synthesized compound was confirmed through satisfactory spectroscopic (nmr and ir) and analytical (elemental and/or mass spectral) data. The conclusion of the research was the successful completion of a general and regiospecific synthesis route for ellipticine, which could potentially be adapted for the synthesis of other related alkaloids.
10.1039/c39920000418
The research focused on the photochemical reaction of β-hydroxyketones, specifically 3-hydroxy-1-(o-methylaryl)-2,2,4-trimethylpentan-1-ones, with the aim of understanding the effect of β-functional groups on the photoreactivity of ketones. The study aimed to explore the formation of cyclopropane-1,2-diols, 1,3-diketones, and benzocylobutenols upon irradiation in methanol. The researchers found that irradiation of these compounds led to the formation of cyclopropane-1,2-diols, which were previously thought to be sensitive to air and rapidly oxidized to 1,3-diketones. The study concluded that the formation of these cyclopropane-1,2-diols could be rationalized by the abstraction of hydrogen on C(3) activated by the hydroxy group, followed by cyclization of the resulting 1,3-diradical. The chemicals used in the process included the β-hydroxyketones themselves, methanol as the solvent, and phenylboronic acid for the cyclic esterification to establish the configurations of the cyclopropanediols.
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.
10.3762/bjoc.8.59
The research aimed on the synthesis of 2-deoxy-2-C-alkyl/aryl septanosides, which are unnatural seven-membered cyclic sugars, using a common bromo-oxepine intermediate. The purpose of the study was to explore the reactivity of bromo-oxepine in the synthesis of septanosides, branching out at C-2, through C–C bond formation with alkyl and aryl substituents. The researchers utilized C–C bond forming organometallic reactions such as Heck, Suzuki, and Sonogashira coupling reactions with various substrates including acrylates, arylboronic acids, and alkynes. The conclusions drawn from the study demonstrated the effective application of bromo-oxepine for the preparation of previously unknown 2-deoxy-2-C-alkyl/aryl septanoside derivatives, highlighting the scope of seven-membered bromo-oxepines as useful substrates for generating these septanosides. Key chemicals used in the process included phenylboronic acid, substituted phenylboronic acids, acetylenes, Pd(OAc)2, Pd(PPh3)2Cl2, CuI, and various acrylates and styrenes.
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