scholarly journals Recyclable Cu salt-derived Brønsted acids for hydrolytic hydrogenation of cellulose on Ru catalyst

CCS Chemistry ◽  
2021 ◽  
pp. 1-17
Author(s):  
Yue Liu ◽  
Linxiao Chen ◽  
Wei Zhang ◽  
Haichao Liu
Keyword(s):  
Bronsted Acids ◽  
Ru Catalyst ◽  
Hydrolytic Hydrogenation

Influence of ZrO2 on catalytic performance of Ru catalyst in hydrolytic hydrogenation of cellulose towards γ-valerolactone

2016 ◽  
Vol 41 (20) ◽  
pp. 8688-8695 ◽  
Author(s):  
Małgorzata Wąchała ◽  
Jacek Grams ◽  
Witold Kwapiński ◽  
Agnieszka M. Ruppert
Keyword(s):  
Catalytic Performance ◽  
Ru Catalyst ◽  
Hydrolytic Hydrogenation

One-Pot Synthesis and Conformational Analysis of 6-Membered Cyclic Iodonium Salts

2020 ◽  
Author(s):  
Lucien Caspers ◽  
Julian Spils ◽  
Mattis Damrath ◽  
Enno Lork ◽  
Boris Nachtsheim
Keyword(s):  
Conformational Analysis ◽  
Bronsted Acids ◽  
One Pot ◽  
Benzyl Alcohols ◽  
Iodonium Salts ◽  
Efficient Approach ◽  
One Pot Synthesis ◽  
Diaryliodonium Salts

In this article we describe an efficient approach for the synthesis of cyclic diaryliodonium salts. The method is based on benzyl alcohols as starting materials and consists of an Friedel-Crafts-arylation/oxidation sequence. Besides a deep optimization, particluar focusing on the choice and ratios of the utilized Bronsted-acids and oxidants, we explore the substrate scope of this transformation. We also discuss an interesting isomerism of cyclic iodonium salts substituted with aliphatic substituents at the bridge head carbon. <br>

Stereoretentive Olefin Metathesis: A New Avenue for the Synthesis of All-cis Poly(p-phenylene vinylene)s and Stereo­defined Polyalkenamers

Synlett ◽  
2021 ◽  
Author(s):  
Quentin Michaudel ◽  
Samuel J. Kempel ◽  
Ting-Wei Hsu
Keyword(s):  
Olefin Metathesis ◽  
Ring Opening ◽  
Diblock Copolymers ◽  
Catalyst Design ◽  
Phenylene Vinylene ◽  
Grand Challenge ◽  
Ru Catalyst ◽  
Unique Reaction ◽  
Photochemical Isomerization ◽  
Optimized Conditions

AbstractOlefin metathesis has tremendously impacted all fields of synthetic chemistry. However, the control of the olefin stereochemistry during this process remains a grand challenge. Recent innovations in catalyst design have permitted control of the stereochemistry of the olefin product. Here, we discuss the development of stereoretentive olefin metathesis, with an emphasis on the synthesis of stereodefined polyalkenamers through ring-opening metathesis polymerization (ROMP). We then present our application of this unique reaction manifold to the preparation of all-cis poly(p-phenylene vinylene)s (PPVs). A dithiolate Ru catalyst was found to deliver perfect cis selectivity for the polymerization of a paracyclophane diene monomer. By using optimized conditions, all-cis PPVs with narrow dispersities and predictable molar masses were obtained by varying the ratio of monomer to catalyst. The high chain fidelity of the stereoretentive ROMP with a paracyclophane diene monomer enabled the preparation of well-defined diblock copolymers with a norbornene co-monomer. Photochemical isomerization of all-cis to all-trans PPVs was effected with both homopolymers and diblock copolymers. This process was shown to be selective for the PPV block, and resulted in changes in optical properties, polymer size, and solubility. Stereoretentive ROMP provides a promising platform for synthesizing polymers with unique properties, including photoresponsive all-cis PPVs with living characteristics.1 Introduction2 Synthetic Applications of Stereoretentive Olefin Metathesis3 Stereocontrol of Polyalkenamers through Stereoretentive ROMP4 Stereoretentive ROMP To Access All-cis Poly(p-phenylene vinylene)s5 Conclusion

scholarly journals Chemoselective hydrogenation of heteroarenes and arenes by Pd–Ru–PVP under mild conditions

RSC Advances ◽  
2020 ◽  
Vol 10 (72) ◽  
pp. 44191-44195
Author(s):  
Chandan Chaudhari ◽  
Katsutoshi Sato ◽  
Yoshihide Nishida ◽  
Tomokazu Yamamoto ◽  
Takaaki Toriyama ◽  
...  
Keyword(s):  
Ru Catalyst ◽  
Mild Conditions ◽  
Chemoselective Hydrogenation

Recyclable Pd0.5Ru0.5–PVP catalyst showed higher activity than monometallic Pd or Ru catalyst for the hydrogenation of quinoline. Furthermore, Pd0.5Ru0.5–PVP was able to hydrogenate different arenes.

Methane synthesis from CO2 and H2O with electricity using H-permeable membrane electrochemical cells with Ru catalyst and phosphate electrolyte

2021 ◽  
Vol 5 (4) ◽  
pp. 935-940
Author(s):  
Jun Kubota ◽  
Takaya Okumura
Keyword(s):  
Current Efficiency ◽  
Electrochemical Cells ◽  
Permeable Membrane ◽  
Ru Catalyst ◽  
Electrochemical Conversion ◽  
A Current ◽  
Phosphate Electrolyte

Direct electrochemical conversion of CO2 and H2O to CH4 in a combined Ru-catalyst and H2O electrolyzer system was examined at 270 °C, thus obtaining a current efficiency of 93% for CH4 formation.

scholarly journals Recent Advances in Transition-Metal-Free (4+3)-Annulations

Synthesis ◽  
2021 ◽  
Author(s):  
Heather Lam ◽  
Mark Lautens ◽  
Xavier Abel-Snape ◽  
Martin F. Köllen
Keyword(s):  
Transition Metal ◽  
Boronic Acid ◽  
Lewis Acids ◽  
Acid Catalysis ◽  
Heterocyclic Carbenes ◽  
Bronsted Acids ◽  
Metal Free ◽  
Previous Review ◽  
Dual Activation ◽  
Metal Catalyzed

Abstract(4+3)-Annulations are incredibly versatile reactions which combine a 4-atom synthon and a 3-atom synthon to form both 7-membered carbocycles as well as heterocycles. We have previously reviewed transition-metal-catalyzed (4+3)-annulations. In this review, we will cover examples involving bases, NHCs, phosphines, Lewis and Brønsted acids as well as some rare examples of boronic acid catalysis and photocatalysis. In analogy to our previous review, we exclude annulations involving cyclic dienes like furan, pyrrole, cyclohexadiene or cyclopentadiene, as Chiu, Harmata, Fernándes and others have recently published reviews encompassing such substrates. We will however discuss the recent additions (2010–2020) to the literature on (4+3)-annulations involving other types of 4-atom-synthons.1 Introduction2 Bases3 Annulations Using N-Heterocyclic Carbenes3.1 N-Heterocyclic Carbenes (NHCs)3.2 N-Heterocyclic Carbenes and Base Dual-Activation4 Phosphines5 Acids5.1 Lewis Acids5.2 Brønsted Acids6 Boronic Acid Catalysis and Photocatalysis7 Conclusion

Enantioselective Bromocyclization of Tryptamines Induced by Chiral Co(III)-Complex-Templated Brønsted Acids under an Air Atmosphere

2018 ◽  
Vol 83 (12) ◽  
pp. 6815-6823 ◽  
Author(s):  
Kun Liu ◽  
Hua-Jie Jiang ◽  
Na Li ◽  
Hui Li ◽  
Jing Wang ◽  
...  
Keyword(s):  
Bronsted Acids ◽  
Air Atmosphere
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