370-99-0Relevant academic research and scientific papers
Solvent and base dependence of copper-free palladium-catalyzed cross-couplings between terminal alkynes and arylic iodides: Development of efficient conditions for the construction of gold(III)/free-base porphyrin dimers
Ljungdahl, Thomas,Pettersson, Karin,Albinsson, Bo,Martensson, Jerker
, p. 1677 - 1687 (2006)
In this paper, our attempts to optimize the Heck alkynylation (copper-free Sonogashira) reaction are presented. An efficient copper-free coupling protocol was needed for the synthesis of gold/zinc porphyrin dimers because previous methods had failed. Prev
Estimation of the Fraction of Spin-Correlated Radical Ion Pairs in Irradiated Alkanes using Magnetosensitive Recombination Luminescence from Exciplexes Generated upon Recombination of a Probe Pair
Melnikov, Anatoly R.,Verkhovlyuk, Vladimir N.,Kalneus, Evgeny V.,Korolev, Valeri V.,Borovkov, Vsevolod I.,Sherin, Peter S.,Davydova, Maria P.,Vasilevsky, Sergei F.,Stass, Dmitri V.
, p. 239 - 267 (2017)
We suggest a convenient probe exciplex system for studies in radiation spin chemistry based on a novel acceptor-substituted diphenylacetylene, 1-(phenylethynyl)-4-(trifluoromethyl)benzene that has a very short fluorescence lifetime (a shifted to red exciplex emission band as compared to the parent system DMA-diphenylacetylene. After chemical, luminescent, radiation and spin-chemical characterization of the new system we used the magnitude of magnetic field effect in its exciplex emission band for experimental estimation of the fraction of spin-correlated radical ion pairs under X-irradiation with upper energy cutoff 40 keV in a set of 11 alkanes. For linear and branched alkanes magnetic field effects and the corresponding fractions are approximately 19-20% and 0.28, while for cyclic alkanes they are lower at 16-17% and 0.22, respectively.
On the catalytic cycle of the palladium-catalyzed cross-coupling reaction of alkynylstannane with aryl iodide
Shirakawa, Eiji,Yoshida, Hiroto,Hiyama, Tamejiro
, p. 5177 - 5180 (1997)
The coupling reaction of phenylethynyltributyltin with (4-trifluoromethyl)iodobenzene catalyzed by a Pd(0) complex coordinated by N-(2-diphenylphosphinobenzylidene)-2-phenylethylamine was found to start with oxidative addition of the tin reagent to the Pd
Kinetic analysis of aqueous-phase Pd-catalyzed, Cu-free direct arylation of terminal alkynes using a hydrophilic ligand
Domier, Ria C.,Moore, Jane N.,Shaughnessy, Kevin H.,Hartman, Ryan L.
, p. 1262 - 1271 (2013)
The engineering of reaction mixtures that ensure the solubility of inorganic salt byproducts without compromising the reactivity is a grand challenge for continuous flow manufacturing in upstream pharmaceuticals and fine chemicals process development. Aqueous cross-coupling reactions are possible solutions. We report the study of an aqueous phase Pd-catalyzed Cu-free direct arylation of an alkyne using a hydrophilic ligand towards understanding the role of water on the cross-coupling kinetics. Kinetic analyses of theoretically estimated molar flux rates and the measured reaction kinetics reveal a transition from mass transfer to kinetically controlled deprotonation and carbopalladation mechanisms. Interfacial contact areas of immiscible aqueous-organic phases control the crossover from the mass-transfer-limited to the reaction-rate-limited regime. Highly agitated batch reactors and multiphase capillary flow reactors are needed to overcome the mass transport limitations and, thus, discover the transition from the apparent reaction kinetics to the true reaction kinetics. Comparison of previously reported Density Functional Theory calculations with experimentally measured activation energies, ranging from 14.8 to 20.0 kcal/mol, elucidates the theoretical possibility of designing the aqueous phase C-C cross-coupling reaction with similar reactivity as purely organic reactions. Although ambiguity remains concerning which reaction step is rate-determining in either the deprotonation or the carbopalladation mechanism, our discovery undergirds that one mechanism or the other could dominate in aqueous designed direct arylations.
Ligand-free (: Z)-selective transfer semihydrogenation of alkynes catalyzed by in situ generated oxidizable copper nanoparticles
Grela, Karol,Kusy, Rafa?
supporting information, p. 5494 - 5502 (2021/08/16)
Herein, we present (Z)-selective transfer semihydrogenation of alkynes based on in situ generated CuNPs in the presence of hydrogen donors, such as ammonia-borane and a green protic solvent. This environmentally friendly method is characterized by operational simplicity combined with high stereo- and chemoselectivity and functional group compatibility. Auto-oxidation of CuNPs after the completion of a semihydrogenation reaction results in the formation of a water-soluble ammonia complex, so that the catalyst may be reused several times by simple phase-separation with no need for any special regeneration processes. Formed NH4B(OR)4 can be easily transformed back into ammonia-borane or into boric acid. In addition, a one-pot tandem sequence involving a Suzuki reaction followed by semihydrogenation was presented, which allows minimization of chemical waste production.
Selective Phosphoranation of Unactivated Alkynes with Phosphonium Cation to Achieve Isoquinoline Synthesis
Cui, Hong,Bai, Jinku,Ai, Tianyu,Zhan, Ye,Li, Guanzhong,Rao, Honghua
supporting information, p. 4023 - 4028 (2021/05/26)
We herein develop a selective phosphoranation of alkynes with phosphonium cation, which directs a concise approach to isoquinolines from unactivated alkyne and nitrile feedstocks in a single step. Mechanistic studies suggest that the annulation reaction is initiated by the unprecedented phosphoranation of alkynes, thus representing a unique reaction pattern of phosphonium salts and distinguishing it from existing protocols that largely rely on the utilization of highly functionalized imines/oximes and/or highly polarized alkynes.
A simple and efficientin situgenerated copper nanocatalyst for stereoselective semihydrogenation of alkynes
Park, Byoung Yong,Lim, Taeho,Han, Min Su
supporting information, p. 6891 - 6894 (2021/07/19)
Development of a simple, effective, and practical method for (Z)-selective semihydrogenation of alkynes has been considered necessary for easy-to-access applications at organic laboratory scales. Herein, (Z)-selective semihydrogenation of alkynes was achieved using a copper nanocatalyst which was generatedin situsimply by adding ammonia borane to an ethanol solution of copper sulfate. Different types of alkynes including aryl-aryl, aryl-alkyl, and aliphatic alkynes were selectively reduced to (Z)-alkenes affording up to 99% isolated yield. The semihydrogenation of terminal alkynes to alkenes and gram-scale applications were also reported. In addition to eliminating catalyst preparation, the proposed approach is simple and practical and serves as a suitable alternative method to the conventional Lindlar catalyst.
Selective Synthesis of Non-Aromatic Five-Membered Sulfur Heterocycles from Alkynes by using a Proton Acid/N-Chlorophthalimide System
Yu, Wentao,Zhu, Baiyao,Shi, Fuxing,Zhou, Peiqi,Wu, Wanqing,Jiang, Huanfeng
supporting information, p. 1313 - 1322 (2020/12/01)
A multicomponent strategy to achieve two different regioselectivities from alkynes, isothiocyanates and H2O with a proton acid/N-chlorophthalimide (NCPI) system is described to selectively obtain non-aromatic five-membered sulfur heterocycles (1,3-oxathiol-2-imines/thiazol-2(3H)-one derivatives) through multiple bond formations. The process features readily available starting materials, mild reaction conditions, broad substrate scope, good functional-group tolerance, high regio- and chemo- selectivities, gram-scale synthesis and late-stage modifications. Mechanistic studies support the proposal that the transformation process includes a combination of H2O and isothiocyanate, free-radical formation, carbonation and intramolecular cyclization to give the products. Furthermore, the 1,3-oxathiol-2-imine derivatives possess unique fluorescence characteristics and can be used as Pd2+ sensors with a “turn-off” response, demonstrating potential applications in environmental and biological fields.
Lipids as versatile solvents for chemical synthesis
Bayer, Annette,Gevorgyan, Ashot,Hopmann, Kathrin H.
supporting information, p. 7219 - 7227 (2021/09/28)
Development of safe, renewable, cheap and versatile solvents is a longstanding challenge in chemistry. We show here that vegetable oils and related systems can become prominent solvents for organic synthesis. Suzuki-Miyaura, Hiyama, Stille, Sonogashira and Heck cross-couplings proceed with quantitative yields in a range of vegetable oils, fish oil, butter and waxes used as solvents. Appropriate methodologies for high-throughput screening and sustainable isolation techniques applicable for vegetable oils and related lipids are presented.
Ligand-Promoted Alkynylation of Aryl Ketones: A Practical Tool for Structural Diversity in Drugs and Natural Products
Xu, Hui,Ma, Biao,Fu, Zunyun,Li, Han-Yuan,Wang, Xing,Wang, Zhen-Yu,Li, Ling-Jun,Cheng, Tai-Jin,Zheng, Mingyue,Dai, Hui-Xiong
, p. 1758 - 1764 (2021/02/09)
Conversion of the numerous aryl ketones into aryl electrophiles via Ar-C(O) cleavage remains a challenging yet highly desirable transformation in Sonogashira-type coupling. Herein, we report a palladium-catalyzed ligand-promoted alkynylation of unstrained aryl ketones. The protocol allows the alkynylation to be carried out in a one-pot procedure with broad functional-group tolerance and substrate scope. The potential applications of this protocol in drug discovery and chemical biology are further demonstrated by late-stage diversification of a number of pharmaceuticals and natural products. More importantly, two different biologically important fragments derived from a pharmaceutical and natural product could be connected by the consecutive alkynylation of ketones. Distinct from aryl halides in conventional Sonogashira reactions, the protocol provides a practical tool for the 1,2-bifunctionalization of aryl ketone by merging ketone-directed ortho-C-H activation with ligand-promoted ipso-Ar-C(O) alkynylation.
