37580-82-8Relevant academic research and scientific papers
Oxidative carbon-carbon bond cleavage of 1,2-diols to carboxylic acids/ketones by an inorganic-ligand supported iron catalyst
Chen, Weiming,Xie, Xin,Zhang, Jian,Qu, Jian,Luo, Can,Lai, Yaozhu,Jiang, Feng,Yu, Han,Wei, Yongge
supporting information, p. 9140 - 9146 (2021/11/23)
The carbon-carbon bond cleavage of 1,2-diols is an important chemical transformation. Although traditional stoichiometric and catalytic oxidation methods have been widely used for this transformation, an efficient and valuable method should be further explored from the views of reusable catalysts, less waste, and convenient procedures. Herein an inorganic-ligand supported iron catalyst (NH4)3[FeMo6O18(OH)6]·7H2O was described as a heterogeneous molecular catalyst in acetic acid for this transformation in which hydrogen peroxide was used as the terminal oxidant. Under the optimized reaction conditions, carbon-carbon bond cleavage of 1,2-diols could be achieved in almost all cases and carboxylic acids or ketones could be afforded with a high conversion rate and high selectivity. Furthermore, the catalytic system was used efficiently to degrade renewable biomass oleic acid. Mechanistic insights based on the observation of the possible intermediates and control experiments are presented.
Mo–Catalyzed One-Pot Synthesis of N-Polyheterocycles from Nitroarenes and Glycols with Recycling of the Waste Reduction Byproduct. Substituent-Tuned Photophysical Properties
Hernández-Ruiz, Raquel,Rubio-Presa, Rubén,Suárez-Pantiga, Samuel,Pedrosa, María R.,Fernández-Rodríguez, Manuel A.,Tapia, M. José,Sanz, Roberto
supporting information, p. 13613 - 13623 (2021/08/23)
A catalytic domino reduction–imine formation–intramolecular cyclization–oxidation for the general synthesis of a wide variety of biologically relevant N-polyheterocycles, such as quinoxaline- and quinoline-fused derivatives, and phenanthridines, is reported. A simple, easily available, and environmentally friendly dioxomolybdenum(VI) complex has proven to be a highly efficient and versatile catalyst for transforming a broad range of starting nitroarenes involving several redox processes. Not only is this a sustainable, step-economical as well as air- and moisture-tolerant method, but also it is worth highlighting that the waste byproduct generated in the first step of the sequence is recycled and incorporated in the final target molecule, improving the overall synthetic efficiency. Moreover, selected indoloquinoxalines have been photophysically characterized in cyclohexane and toluene with exceptional fluorescence quantum yields above 0.7 for the alkyl derivatives.
Metal-free thermal organocatalytic pinacol coupling of arylaldehydes using an isonicotinate catalyst with bis(pinacolato)diboron
Hanaya, Kengo,Higashibayashi, Shuhei,Sugai, Takeshi,Yasui, Masamichi
, p. 24652 - 24655 (2021/07/29)
The metal-free thermal organocatalytic pinacol coupling of arylaldehydes has been developed. The intermolecular coupling of arylaldehydes catalyzed byt-butyl isonicotinate with bis(pinacolato)diboron as the co-reducing agent afforded 1,2-diphenylethane-1,2-diols. This reaction was also applicable to the intramolecular coupling of 1,1′-biphenyl-2,2′-dicarbaldehydes to afford 9,10-dihydrophenanthrene-9,10-diols. Various functional groups were tolerated under this coupling condition.
Oxidative and Redox-Neutral Approaches to Symmetrical Diamines and Diols by Single Electron Transfer/Hydrogen Atom Transfer Synergistic Catalysis
Fujita, Masashi,Kobayashi, Fumihisa,Ide, Takafumi,Egami, Hiromichi,Hamashima, Yoshitaka
supporting information, p. 7151 - 7155 (2020/12/01)
Homocoupling reactions of benzylamines and benzyl alcohols were examined under synergistic catalysis conditions with a photoredox catalyst and thiobenzoic acid as a hydrogen atom abstractor. When pivalaldehyde was used as an electron acceptor, oxidative dimerization proceeded selectively, whereas the use of benzaldehydes or iminium ions as electron acceptors resulted in redox-neutral coupling. These reactions afforded symmetrical 1,2-diamines and 1,2-diols in good yields.
Stereoselective Barbier-Type Allylations and Propargylations Mediated by CpTiCl3
López-Martínez, Josefa L.,Torres-García, Irene,Rodríguez-García, Ignacio,Mu?oz-Dorado, Manuel,álvarez-Corral, Miriam
, p. 806 - 816 (2019/01/24)
CpTiCl2, prepared in situ by manganese reduction of CpTiCl3, is an excellent new system for the Barbier-type allylation and propargylation of carbonyl compounds. It can be used in catalytic amounts when combined with Et3N·HBr/TMSBr, which acts as a regenerating system. The high regio- and stereoselectivity shown by this system makes it useful for prenylation and crotylation processes in the synthesis of natural products.
Bifunctional copper-based photocatalyst for reductive pinacol-type couplings
Caron, Antoine,Morin, émilie,Collins, Shawn K.
, p. 9458 - 9464 (2019/10/11)
A bifunctional copper-based photocatalyst has been prepared that employs a pyrazole-pyridine ligand incorporating a sulfonamide moiety that functions as an intramolecular hydrogen-bond donor for a photochemical PCET process. In typical reductive PCET processes, the photocatalyst and H-bond donor must have an appropriate redox potential and pKa, respectively, to promote the PCET. When working in concert in a bifunctional catalyst such as Cu(pypzs)(BINAP)BF4, the pKa of the H-bond donor can have an acidity that is orders of magnitude less and still efficiently promote the PCET process. A reductive pinacol-type coupling can be performed using a base-metal derived photocatalyst to afford valuable diols (24 examples, 46-99% yield), from readily available aldehydes and ketones.
Hydrogen Bonding-Assisted Enhancement of the Reaction Rate and Selectivity in the Kinetic Resolution of d,l-1,2-Diols with Chiral Nucleophilic Catalysts
Fujii, Kazuki,Mitsudo, Koichi,Mandai, Hiroki,Suga, Seiji
supporting information, p. 2778 - 2788 (2017/08/23)
An extremely efficient acylative kinetic resolution of d,l-1,2-diols in the presence of only 0.5 mol% of binaphthyl-based chiral N,N-4-dimethylaminopyridine was developed (selectivity factor of up to 180). Several key experiments revealed that hydrogen bonding between the tert-alcohol unit(s) of the catalyst and the 1,2-diol unit of the substrate is critical for accelerating the rate of monoacylation and achieving high enantioselectivity. This catalytic system can be applied to a wide range of substrates involving racemic acyclic and cyclic 1,2-diols with high selectivity factors. The kinetic resolution of d,l-hydrobenzoin and trans-1,2-cyclohexanediol on a multigram scale (10 g) also proceeded with high selectivity and under moderate reaction conditions: (i) very low catalyst loading (0.1 mol%); (ii) an easily achievable low reaction temperature (0 °C); (iii) high substrate concentration (1.0 M); and (iv) short reaction time (30 min). (Figure presented.).
Biginelli reaction of vicinal diols: A new route for one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-one derivatives
Jagadishbabu, Narasashetty,Shivashankar, Kalegowda
, p. 330 - 336 (2017/07/26)
Background: 3,4-Dihydropyrimidin-2(1H)-one derivatives are an important class of nitrogen heterocycles. These compounds present a wide range of biological activities viz antibacterial, antifungal, and antidiabetic. Although many synthetic methods are available in the literature for the synthesis of these molecules, many of these methods have their own limitations such as use of excess of expensive catalyst and poor yields. Methods: The synthesis of 3,4-dihydropyrimidin-2(1H)-one derivatives is developed through the reaction of 1,2-diols, ethyl acetoacetate and urea in the presence of lead tetraacetate in dry ethanol under reflux conditions. Results: A series of 3,4-dihydropyrimidin-2(1H)-one derivatives were synthesized in good yields (82-95%) under reflux for 2-3.5 hours in ethanol solvent. The structural assignments of these compounds were made on the basis of elemental analysis and spectroscopic data. Conclusion: This protocol is an alternative to existing procedure for the synthesis of Biginelli compounds. The present methodology reduces the number of steps in total synthesis.
An imidazolium-modified chiral rhodium/diamine-functionalized periodic mesoporous organosilica for asymmetric transfer hydrogenation of α-haloketones and benzils in aqueous medium
Zhou, Feng,Hu, Xiaoying,Gao, Ming,Cheng, Tanyu,Liu, Guohua
, p. 5651 - 5657 (2016/10/21)
The use of a hydrophobic, imidazolium-functionalized periodic mesoporous organosilica for immobilization of chiral organometallic complexes as a heterogeneous catalyst is highly desirable as this catalyst can greatly promote an aqueous organic transformation due to its hydrophobic function and phase-transfer feature in an aqueous medium. Herein, by utilizing a three-component co-condensation strategy, we conveniently incorporate 1,2-bis(triethoxysilyl)ethane, (R,R)-4-((trimethoxysilyl)ethyl)phenylsulfonyl-1,2-diphenylethylene-diamine and 1,3-bis(3-(triethoxysilyl)propyl)-1H-imidazol-3-ium iodide within its silicate network, which is coordinated with (Cp?RhCl2)2, leading to an imidazolium-modified chiral rhodium/diamine-functionalized periodic mesoporous organosilica. A solid-state carbon spectrum discloses its well-defined chiral rhodium/diamine active species, and its X-ray diffraction; nitrogen adsorption-desorption measurement and transmission electron microscopy images reveal its ordered dimensional-hexagonal mesostructure. As a bifunctional heterogeneous catalyst, this periodic mesoporous organosilica significantly boosts asymmetric transfer hydrogenation of α-haloketones and benzils in water, where the hydrophobic periodic mesoporous organosilica, phase-transfer-featured imidazolium-functionality, and the confined chiral organorhodium catalytic nature are responsible for its catalytic performance. Furthermore, the catalyst can be recovered and recycled seven times without the loss of its catalytic activity, making it an attractive heterogeneous catalyst for asymmetric transfer hydrogenation in an environmentally friendly manner.
Polarity-Reversed Allylations of Aldehydes, Ketones, and Imines Enabled by Hantzsch Ester in Photoredox Catalysis
Qi, Li,Chen, Yiyun
supporting information, p. 13312 - 13315 (2016/10/30)
The polarity reversal (umpolung) reaction is an invaluable tool for reversing the chemical reactivity of carbonyl and iminyl groups, which subsequent cross-coupling reactions to form C?C bonds offers a unique perspective in synthetic planning and implementation. Reported herein is the first visible-light-induced polarity-reversed allylation and intermolecular Michael addition reaction of aldehydes, ketones, and imines. This chemoselective reaction has broad substrate scope and the engagement of alkyl imines is reported for the first time. The mechanistic investigations indicate the formation of ketyl (or α-aminoalkyl) radicals from single-electron reduction, where the Hantzsch ester is crucial as the electron/proton donor and the activator.
