scholarly journals Fluoride Migration Catalysis Enables Simple, Stereoselective, and Iterative Glycosylation

2019 ◽  
Author(s):  
Girish Sati ◽  
Joshua Martin ◽  
Yishu Xu ◽  
Tanmay Malakar ◽  
Paul M. Zimmerman ◽  
...  
Keyword(s):  
Room Temperature ◽  
Building Blocks ◽  
Silyl Ether ◽  
One Pot ◽  
Glycoside Synthesis ◽  
Glycosidic Bonds ◽  
Stable Forms

Challenges in the assembly of glycosidic bonds pose a bottleneck in enabling the remarkable promise of advances in the glycosciences. We report a strategy that applies unique features of electrophilic boron catalysts in addressing current limitations of methods in glycoside synthesis. The strategy utilizes glycosyl fluoride donors and silyl ether acceptors while tolerating the Lewis basic environment found in carbohydrates. The method allows a simple setup at room temperature while utilizing catalyst loadings as low as 0.5 mol %, and air- and moisture stable forms of the catalyst are found to be effective. These characteristics enable a wide array of glycosylation patterns to be accessed, including all four C1-C2 stereorelationships, and the method allows one-pot, iterative glycosylations to generate oligosaccharides directly from monosaccharide building blocks.<br>

scholarly journals Fluoride Migration Catalysis Enables Simple, Stereoselective, and Iterative Glycosylation

2019 ◽  
Author(s):  
Girish Sati ◽  
Joshua Martin ◽  
Yishu Xu ◽  
Tanmay Malakar ◽  
Paul M. Zimmerman ◽  
...  
Keyword(s):  
Room Temperature ◽  
Building Blocks ◽  
Silyl Ether ◽  
One Pot ◽  
Glycoside Synthesis ◽  
Glycosidic Bonds ◽  
Stable Forms

Challenges in the assembly of glycosidic bonds pose a bottleneck in enabling the remarkable promise of advances in the glycosciences. We report a strategy that applies unique features of electrophilic boron catalysts in addressing current limitations of methods in glycoside synthesis. The strategy utilizes glycosyl fluoride donors and silyl ether acceptors while tolerating the Lewis basic environment found in carbohydrates. The method allows a simple setup at room temperature while utilizing catalyst loadings as low as 0.5 mol %, and air- and moisture stable forms of the catalyst are found to be effective. These characteristics enable a wide array of glycosylation patterns to be accessed, including all four C1-C2 stereorelationships, and the method allows one-pot, iterative glycosylations to generate oligosaccharides directly from monosaccharide building blocks.<br>

One-Pot Preparation of Stable Organoboronate Reagents for the Functionalization of Unsaturated Four- and Five-Membered Carbo­- and Heterocycles

Synthesis ◽  
2018 ◽  
Vol 50 (16) ◽  
pp. 3149-3160 ◽  
Author(s):  
Dorian Didier ◽  
Andreas Baumann ◽  
Michael Eisold ◽  
Arif Music
Keyword(s):  
Room Temperature ◽  
Functional Group ◽  
Building Blocks ◽  
Boronic Acids ◽  
Ex Situ ◽  
One Pot ◽  
Potential Applicability ◽  
Facile Preparation

Combining a facile preparation of organoboronates with their remarkable stability and functional group tolerance allows for the straightforward synthesis of four- and five-membered carbo- and hetero­cycles. While most strategies rely on the ex situ preparation of boronic acids as isolated intermediates, we demonstrate that in situ transmetalation of sensitive organometallics with boron alkoxides can lead to great stabilization of such species at room temperature. A considerable extension of the library of unsaturated strained structures is achieved through these sequences, expanding the potential applicability of such unusual building blocks.

scholarly journals Integrated Synthesis of Nucleotide and Nucleosides Directed by Amino Acids

2018 ◽  
Author(s):  
Irene Suárez-Marina ◽  
Rebecca Turk-MacLeod ◽  
Yousef M. Abul-Haija ◽  
Piotr S. Gromski ◽  
Geoffrey Cooper ◽  
...  
Keyword(s):  
Amino Acids ◽  
Prebiotic Chemistry ◽  
Building Blocks ◽  
Reaction Networks ◽  
One Pot ◽  
Simultaneous Formation ◽  
Chemical Systems ◽  
Mild Conditions ◽  
Glycosidic Bonds ◽  
Selection Of

<p><b>Research on the origin of nucleic acids and proteins has been approached by either multi-step synthesis or simple one-pot reactions, but exploration of their prebiotic chemistry is normally done separately. However, if nucleotides and amino acids co-existed on early Earth, their mutual interactions and reactivity should be considered in exploring the emergence of complex chemical systems that can ultimately evolve. To explore this idea, we set out to investigate nucleotide/nucleoside formation by a simple dehydration reaction of the constituent building blocks (sugar, phosphate, and nucleobase) in the presence of amino acids (<i>i.e.</i> glycine,</b> <b>arginine, glutamic acid, threonine, methionine, phenylalanine and tryptophan). Herein, we report the first example of simultaneous formation of glycosidic bonds between ribose, purines, and pyrimidines under mild conditions without a catalyst or activated reagents, as well as nucleobase exchange. We observed not only the simultaneous formation of nucleotide and nucleoside isomers from several nucleobases, but also the selection of distribution of glycosylation products when glycine was present. This work shows how reaction networks of nucleotides and amino acids should be considered when exploring the emergence of catalytic networks in the context of molecular evolution. </b></p>

scholarly journals Integrated Synthesis of Nucleotide and Nucleosides Directed by Amino Acids

2018 ◽  
Author(s):  
Irene Suárez-Marina ◽  
Rebecca Turk-MacLeod ◽  
Yousef M. Abul-Haija ◽  
Piotr S. Gromski ◽  
Geoffrey Cooper ◽  
...  
Keyword(s):  
Amino Acids ◽  
Prebiotic Chemistry ◽  
Building Blocks ◽  
Reaction Networks ◽  
One Pot ◽  
Simultaneous Formation ◽  
Chemical Systems ◽  
Mild Conditions ◽  
Glycosidic Bonds ◽  
Selection Of

<p><b>Research on the origin of nucleic acids and proteins has been approached by either multi-step synthesis or simple one-pot reactions, but exploration of their prebiotic chemistry is normally done separately. However, if nucleotides and amino acids co-existed on early Earth, their mutual interactions and reactivity should be considered in exploring the emergence of complex chemical systems that can ultimately evolve. To explore this idea, we set out to investigate nucleotide/nucleoside formation by a simple dehydration reaction of the constituent building blocks (sugar, phosphate, and nucleobase) in the presence of amino acids (<i>i.e.</i> glycine,</b> <b>arginine, glutamic acid, threonine, methionine, phenylalanine and tryptophan). Herein, we report the first example of simultaneous formation of glycosidic bonds between ribose, purines, and pyrimidines under mild conditions without a catalyst or activated reagents, as well as nucleobase exchange. We observed not only the simultaneous formation of nucleotide and nucleoside isomers from several nucleobases, but also the selection of distribution of glycosylation products when glycine was present. This work shows how reaction networks of nucleotides and amino acids should be considered when exploring the emergence of catalytic networks in the context of molecular evolution. </b></p>

Room Temperature Alkali Metal Reduction of Carbon Dioxide

2020 ◽  
Author(s):  
Lucas A. Freeman ◽  
Akachukwu D. Obi ◽  
Haleigh R. Machost ◽  
Andrew Molino ◽  
Asa W. Nichols ◽  
...  
Keyword(s):  
Alkali Metal ◽  
Alkali Metals ◽  
Room Temperature ◽  
Chemical Reduction ◽  
Bond Cleavage ◽  
Open Shell ◽  
Metal Reduction ◽  
One Pot ◽  
Earth Abundant ◽  
Electron Reduction

The reduction of the relatively inert carbon–oxygen bonds of CO<sub>2</sub> to access useful CO<sub>2</sub>-derived organic products is one of the most important fundamental challenges in synthetic chemistry. Facilitating this bond-cleavage using earth-abundant, non-toxic main group elements (MGEs) is especially arduous because of the difficulty in achieving strong inner-sphere interactions between CO<sub>2</sub> and the MGE. Herein we report the first successful chemical reduction of CO<sub>2</sub> at room temperature by alkali metals, promoted by a cyclic(alkyl)(amino) carbene (CAAC). One-electron reduction of CAAC-CO<sub>2</sub> adduct (<b>1</b>) with lithium, sodium or potassium metal yields stable monoanionic radicals clusters [M(CAAC–CO<sub>2</sub>)]<sub>n</sub>(M = Li, Na, K, <b> 2</b>-<b>4</b>) and two-electron alkali metal reduction affords open-shell, dianionic clusters of the general formula [M<sub>2</sub>(CAAC–CO<sub>2</sub>)]<sub>n </sub>(<b>5</b>-<b>8</b>). It is notable that these crystalline clusters of reduced CO<sub>2</sub> may also be isolated via the “one-pot” reaction of free CO<sub>2</sub> with free CAAC followed by the addition of alkali metals – a reductive process which does not occur in the absence of carbene. Each of the products <b>2</b>-<b>8</b> were investigated using a combination of experimental and theoretical methods.<br>

A Series of Metal-Organic Frameworks for Selective CO2 Capture and Catalytic Oxidative Carboxylation of Olefins

2018 ◽  
Author(s):  
Huong T. D. Nguyen ◽  
Y B. N. Tran ◽  
Hung N. Nguyen ◽  
Tranh C. Nguyen ◽  
Felipe Gándara ◽  
...  
Keyword(s):  
Room Temperature ◽  
Gas Adsorption ◽  
New Materials ◽  
One Pot ◽  
Acid Gas ◽  
Naphthalene Diimide ◽  
Styrene Carbonate ◽  
Metal Organic ◽  
Adsorption Of Co ◽  
The One

<p>Three novel lanthanide metal˗organic frameworks (Ln-MOFs), namely MOF-590, -591, and -592 were constructed from a naphthalene diimide tetracarboxylic acid. Gas adsorption measurements of MOF-591 and -592 revealed good adsorption of CO<sub>2</sub> (low pressure, at room temperature) and moderate CO<sub>2</sub> selectivity over N<sub>2</sub> and CH<sub>4</sub>. Accordingly, breakthrough measurements were performed on a representative MOF-592, in which the separation of CO<sub>2</sub> from binary mixture containing N<sub>2</sub> and CO<sub>2</sub> was demonstrated without any loss in performance over three consecutive cycles. Moreover, MOF-590, MOF-591, and MOF-592 exhibited catalytic activity in the one-pot synthesis of styrene carbonate from styrene and CO<sub>2</sub> under mild conditions (1 atm CO<sub>2</sub>, 80 °C, and solvent-free). Among the new materials, MOF-590 revealed a remarkable efficiency with exceptional conversion (96%), selectivity (95%), and yield (91%). </p><br>

Synthesis of Nitrile-Bearing Quaternary Centers via an Equilibrium-Driven Transnitrilation and Anion-Relay Strategy

2019 ◽  
Author(s):  
Sebastien Alazet ◽  
Michael West ◽  
Purvish Patel ◽  
Sophie Rousseaux
Keyword(s):  
Building Blocks ◽  
One Pot ◽  
Quaternary Centers ◽  
Synthetic Intermediates

The efficient preparation of nitrile-containing building blocks is of interest due to their utility as synthetic intermediates and their prevalence in pharmaceuticals. As a result, significant efforts have been made to develop methods to access these motifs which rely on safer and non-toxic sources of CN. Herein, we report that 2-methyl-2-phenylpropanenitrile is an efficient, non-toxic, electrophilic CN source for the synthesis of nitrile-bearing quaternary centers via a thermodynamic transnitrilation and anion-relay strategy. This one-pot process leads to nitrile products resulting from the gem-difunctionalization of alkyl lithium reagents.<br>

A Study on the Rearrangement of Dialkyl 1-Aryl-1-hydroxymethylphosphonates to Benzyl Phosphates

2020 ◽  
Vol 24 (4) ◽  
pp. 465-471 ◽  
Author(s):  
Zita Rádai ◽  
Réka Szabó ◽  
Áron Szigetvári ◽  
Nóra Zsuzsa Kiss ◽  
Zoltán Mucsi ◽  
...  
Keyword(s):  
Quantum Chemical ◽  
Room Temperature ◽  
Phase Transfer ◽  
One Pot ◽  
Substrate Dependence ◽  
Triethylbenzylammonium Chloride ◽  
One Step ◽  
The Pudovik Reaction ◽  
The One ◽  
Solid Liquid

The phospha-Brook rearrangement of dialkyl 1-aryl-1-hydroxymethylphosphonates (HPs) to the corresponding benzyl phosphates (BPs) has been elaborated under solid-liquid phase transfer catalytic conditions. The best procedure involved the use of triethylbenzylammonium chloride as the catalyst and Cs2CO3 as the base in acetonitrile as the solvent at room temperature. The substrate dependence of the rearrangement has been studied, and the mechanism of the transformation under discussion was explored by quantum chemical calculations. The key intermediate is an oxaphosphirane. The one-pot version starting with the Pudovik reaction has also been developed. The conditions of this tandem transformation were the same, as those for the one-step HP→BP conversion.

One-pot Synthesis of Pyrazolone Sulfones by Iodine-catalyzed Sulfenylation of Pyrazolones with Aryl Sulfonyl Hydrazides Followed by Oxidation in Water

2018 ◽  
Vol 15 (3) ◽  
pp. 380-387
Author(s):  
Xia Zhao ◽  
Xiaoyu Lu ◽  
Lipeng Zhang ◽  
Tianjiao Li ◽  
Kui Lu
Keyword(s):  
Double Bond ◽  
Efficient Method ◽  
Room Temperature ◽  
Sulfonyl Chloride ◽  
Antibacterial Activities ◽  
Oxidation Reactions ◽  
Reaction Conditions ◽  
One Pot ◽  
X Ray ◽  
Amide Form

Aim and Objective: Pyrazolone sulfones have been reported to exhibit herbicidal and antibacterial activities. In spite of their good bioactivities, only a few methods have been developed to prepare pyrazolone sulfones. However, the substrate scope of these methods is limited. Moreover, the direct sulfonylation of pyrazolone by aryl sulfonyl chloride failed to give pyrazolone sulfones. Thus, developing a more efficient method to synthesize pyrazolone sulfones is very important. Materials and Method: Pyrazolone, aryl sulphonyl hydrazide, iodine, p-toluenesulphonic acid and water were mixed in a sealed tube, which was heated to 100°C for 12 hours. The mixture was cooled to 0°C and m-CPBA was added in batches. The mixture was allowed to stir for 30 min at room temperature. The crude product was purified by silica gel column chromatography to afford sulfuryl pyrazolone. Results: In all cases, the sulfenylation products were formed smoothly under the optimized reaction conditions, and were then oxidized to the corresponding sulfones in good yields by 3-chloroperoxybenzoic acid (m-CPBA) in water. Single crystal X-ray analysis of pyrazolone sulfone 4aa showed that the major tautomer of pyrazolone sulfones was the amide form instead of the enol form observed for pyrazolone thioethers. Moreover, the C=N double bond isomerized to form an α,β-unsaturated C=C double bond. Conclusion: An efficient method to synthesize pyrazolone thioethers by iodine-catalyzed sulfenylation of pyrazolones with aryl sulfonyl hydrazides in water was developed. Moreover, this method was employed to synthesize pyrazolone sulfones in one-pot by subsequent sulfenylation and oxidation reactions.

scholarly journals Clean one-pot multicomponent synthesis of pyrans using a green and magnetically recyclable heterogeneous nanocatalyst

SynOpen ◽  
2021 ◽  
Author(s):  
Mina Ghassemi ◽  
Ali Maleki
Keyword(s):  
Room Temperature ◽  
Significant Loss ◽  
Copper Ferrite ◽  
Multicomponent Synthesis ◽  
Thermo Gravimetric ◽  
Sem Images ◽  
One Pot ◽  
Three Component Reaction ◽  
Ft Ir ◽  
The One

Copper ferrite (CuFe2O4) magnetic nanoparticles (MNPs) were synthesized via thermal decomposition method and applied as a reusable and green catalyst in the synthesis of functionalized 4H-pyran derivatives using malononitrile, an aromatic aldehyde and a β-ketoester in ethanol at room temperature. Then it was characterized by Fourier transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDX) analysis, scanning electron microscopy (SEM) images, thermo gravimetric and differential thermo gravimetric (TGA/DTG) analysis. The catalyst was recovered from the reaction mixture by applying an external magnet and decanting the mixture. Recycled catalyst was reused for several times without significant loss in its activity. Running the one-pot three-component reaction at room temperature, no use of eternal energy source and using a green solvent provide benign, mild, and environmentally friendly reaction conditions; as well, ease of catalyst recovering, catalyst recyclability, no use of column chromatography and good to excellent yields are extra advantages of this work.

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