2189-60-8Relevant academic research and scientific papers
Green synthesis of a palladium-polyaniline nanocomposite for green Suzuki-Miyaura coupling reactions
Dutt, Sunil,Kumar, Raj,Siril, Prem Felix
, p. 33786 - 33791 (2015)
A palladium-polyaniline (Pd-PANI) nanocomposite was successfully synthesized using a one-pot green synthetic procedure in water by the reaction between aniline hydrochloride and potassium hexachloropalladate. Strong interaction between PANI and Pd was clearly evident in the UV-visible and Fourier transform infrared (FTIR) spectrum of the nanocomposite. Powder X-ray diffraction (XRD) patterns revealed the presence of Pd(0) in the nanocomposite with a fcc crystal structure. Field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) imaging showed that the Pd-PANI nanocomposite has spherical morphology with an average particle size of 175 ± 42 nm. High resolution TEM imaging and energy dispersive X-ray (EDX) spectroscopy studies revealed that very small nanoparticles of Pd (3.1 ± 0.9 nm) were found dispersed throughout the PANI matrix. X-ray photoelectron spectroscopy (XPS) revealed the presence of Pd(0) in the nanocomposite. The catalytic behavior of the Pd-PANI nanocomposite was studied for Suzuki-Miyaura coupling reactions in the presence of different bases in both organic and aqueous media. The results revealed that the Suzuki-Miyaura reaction proceeds much faster in water than in toluene. The excellent catalytic activity of the nanocomposite resulted in 86 and 91% yield in water and toluene respectively, when potassium carbonate was used as the base.
Ligand redox effects in the synthesis, electronic structure, and reactivity of an alkyl-alkyl cross-coupling catalyst
Jones, Gavin D.,Martin, Jason L.,McFarland, Chris,Allen, Olivia R.,Hall, Ryan E.,Haley, Aireal D.,Brandon, R. Jacob,Konovalova, Tatyana,Desrochers, Patrick J.,Pulay, Peter,Vicic, David A.
, p. 13175 - 13183 (2006)
The ability of the terpyridine ligand to stabilize alkyl complexes of nickel has been central in obtaining a fundamental understanding of the key processes involved in alkyl-alkyl cross-coupling reactions. Here, mechanistic studies using isotopically labeled (TMEDA)NiMe2 (TMEDA = N,N,N′,N′-tetramethylethylenediamine) have shown that an important catalyst in alkyl-alkyl cross-coupling reactions, (tpy′)NiMe (2b, tpy′ = 4,4′,4″-tri-tert-butylterpyridine), is not produced via a mechanism that involves the formation of methyl radicals. Instead, it is proposed that (terpyridine)NiMe complexes arise via a comproportionation reaction between a Ni(II)-dimethyl species and a Ni(0) fragment in solution upon addition of a terpyridine ligand to (TMEDA)NiMe2. EPR and DFT studies on the paramagnetic (terpyridine)NiMe (2a) both suggest that the unpaired electron resides heavily on the terpyridine ligand and that the proper electronic description of this nickel complex is a Ni(II)-methyl cation bound to a reduced terpyridine ligand. Thus, an important consequence of these results is that alkyl halide reduction by (terpyridine)NiRalkyl complexes appears to be substantially ligand based. A comprehensive survey investigating the catalytic reactivity of related ligand derivatives suggests that electronic factors only moderately influence reactivity in the terpyridine-based catalysis and that the most dramatic effects arise from steric and solubility factors.
An alternative efficient approach for the synthesis of Fingolimod hydrochloride
Vinigari, Krishna,Jonnada, Krishna,Mohammed, Noorjahan,Kotu, Girija Mangatayaru
, p. 39 - 48 (2019)
An efficient process for the synthesis of API Fingolimod Hydrochloride is presented. This proposed synthesis involves simple commercially available octanophenone as a starting material. The route is effective involving seven steps to achieve the target, thus reducing the cycle time, and is cost efficient by 50%. It is an immune modulating drug for the treatment of heart failure and arrhythmias.
Cobalt(II) complexes bearing a bulky N-heterocyclic carbene for catalysis of Kumada-Tamao-Corriu cross-coupling reactions of aryl halides
Matsubara, Kouki,Sueyasu, Tsukasa,Esaki, Mariko,Kumamoto, Aya,Nagao, Shinya,Yamamoto, Hitomi,Koga, Yuji,Kawata, Satoshi,Matsumoto, Taisuke
, p. 3079 - 3086 (2012)
Cobalt(II) iodide, bromide, and chloride react with 1 equiv. of IPr [1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene] to form a series of tetrahedral dimeric (30e) complexes of cobalt(II) in good yields. These were transformed into the monomeric forms in the presence of pyridine. These complexes were characterized by SQUID, XPS, UV/Vis spectroscopy, elemental analysis, and X-ray crystallography, and were found to have high catalytic activity for Kumada-Tamao-Corriu cross-coupling reactions of aryl halides. Copyright
A Ball-Milling-Enabled Cross-Electrophile Coupling
Jones, Andrew C.,Nicholson, William I.,Leitch, Jamie A.,Browne, Duncan L.
supporting information, p. 6337 - 6341 (2021/08/23)
The nickel-catalyzed cross-electrophile coupling of aryl halides and alkyl halides enabled by ball-milling is herein described. Under a mechanochemical manifold, the reductive C-C bond formation was achieved in the absence of bulk solvent and air/moisture sensitive setups, in reaction times of 2 h. The mechanical action provided by ball milling permits the use of a range of zinc sources to turnover the nickel catalytic cycle, enabling the synthesis of 28 cross-electrophile coupled products.
Palladium and Nickel Catalyzed Suzuki Cross-Coupling with Alkyl Fluorides
Balaraman, Kaluvu,Wolf, Christian
supporting information, p. 8994 - 8999 (2021/11/20)
Suzuki cross-coupling of benzylic and unactivated aliphatic fluorides with aryl- and alkenylboronic acids has been achieved via mechanistically distinct Pd and Ni catalyzed pathways that outperform competing protodeboronation, β-hydride elimination, and h
Non-innocent Radical Ion Intermediates in Photoredox Catalysis: Parallel Reduction Modes Enable Coupling of Diverse Aryl Chlorides
Chernowsky, Colleen P.,Chmiel, Alyah F.,Wickens, Zachary K.,Williams, Oliver P.,Yeung, Charles S.
supporting information, p. 10882 - 10889 (2021/07/31)
We describe a photocatalytic system that elicits potent photoreductant activity from conventional photocatalysts by leveraging radical anion intermediates generated in situ. The combination of an isophthalonitrile photocatalyst and sodium formate promotes diverse aryl radical coupling reactions from abundant but difficult to reduce aryl chloride substrates. Mechanistic studies reveal two parallel pathways for substrate reduction both enabled by a key terminal reductant byproduct, carbon dioxide radical anion.
A visible-light mediated ring opening reaction of alkylidenecyclopropanes for the generation of homopropargyl radicals
Mao, Ben,Ning, Chao,Shi, Min,Wei, Yin,Zhang, Xiao-Yu
, p. 9088 - 9095 (2021/07/12)
Classical cyclopropylcarbinyl radical clock reactions have been widely applied to conduct mechanistic studies for probing radical processes for a long time; however, alkylidenecyclopropanes, which have a similar molecular structure to methylcyclopropanes, surprisingly have not yet attracted researcher's attention for similar ring opening radical clock processes. In recent years, photocatalytic NHPI ester activation chemistry has witnessed significant blooming developments and provided new synthetic routes for cross-coupling reactions. Herein, we wish to report a non-classical ring opening radical clock reaction using innovative NHPI esters bearing alkylidenecyclopropanes upon photoredox catalysis, providing a brand-new synthetic approach for the direct preparation of a variety of alkynyl derivatives. The potential synthetic utility of this protocol is demonstrated in the diverse transformations and facile synthesis of bioactive molecules or their derivatives and medicinal substances.
Transition Metal-Free sp3?sp3 Carbon-Carbon Coupling between Benzylboronic Esters and Alkyl Bromides
Barker, Timothy J.,Russell, Richard W.
supporting information, p. 2782 - 2784 (2021/06/25)
A transition metal-free coupling reaction of benzylboronic esters and alkyl halides has been developed. Both alkyl bromides and alkyl iodides were found to be competent substrates with the nucleophilic boronate intermediate generated from the combination of benzylboronic ester and an alkyllithium. Good chemoselectivity was observed for the reaction with the alkyl bromide in substrates with a second electrophile present. Both secondary and tertiary benzylboronic esters were effective nucleophiles in the reaction with primary alkyl halides. Mechanistic observations are consistent with a radical mechanism.
Properties and Reactivities of Zwitterionic Platinum(II)-ate Complexes Generated by Transforming Coordination of an Alkyne-Bisphosphine Ligand
Okamoto, Kazuhiro,Sasakura, Kohei,Funasaka, Satoshi,Watanabe, Hiiro,Suezaki, Masahiro,Ohe, Kouichi
, p. 848 - 856 (2021/05/04)
Coordination of an alkyne-bisphosphine ligand with platinum(II) precursors produced a structural reorganization in the ligand backbone to form stable zwitterionic platinum(II) complexes bearing an anionic platinum center. The structural properties and reactivities of these complexes were investigated using X-ray crystallographic analyses, computational studies, and stoichiometric reactions involving oxidative addition and reductive elimination. These studies have shown that the enhanced nucleophilicity of the platinum center to alkyl halides promotes smooth oxidative addition and that the charge rebalance accelerates the dissociation of the halide anion from the platinum(IV) intermediate, which is essential in the carbon-carbon bond-forming step.
