scholarly journals Efficient and selective hydrogenation of amides to alcohols and amines using a well-defined manganese–PNN pincer complex

2017 ◽  
Vol 8 (5) ◽  
pp. 3576-3585 ◽  
Author(s):  
Veronica Papa ◽  
Jose R. Cabrero-Antonino ◽  
Elisabetta Alberico ◽  
Anke Spanneberg ◽  
Kathrin Junge ◽  
...  
Keyword(s):  
Selective Hydrogenation ◽  
Active Catalyst ◽  
Pincer Complexes ◽  
Mild Conditions ◽  
Pincer Complex ◽  
Wide Range ◽  
High Yields

Novel manganese NNP and PNP pincer complexes have been synthesized. The active catalyst allows the efficient hydrogenation of a wide range of amides under relatively mild conditions to afford alcohols and amines in high yields.

scholarly journals Highly selective hydrogenation of amides catalysed by a molybdenum pincer complex: scope and mechanism

2019 ◽  
Vol 10 (45) ◽  
pp. 10566-10576 ◽  
Author(s):  
Thomas Leischner ◽  
Lluis Artús Suarez ◽  
Anke Spannenberg ◽  
Kathrin Junge ◽  
Ainara Nova ◽  
...  
Keyword(s):  
Catalytic Hydrogenation ◽  
Selective Hydrogenation ◽  
Pincer Complexes ◽  
Pincer Complex ◽  
First Time

A series of molybdenum pincer complexes has been shown for the first time to be active in the catalytic hydrogenation of amides.

Additive- and Oxidant-Free Expedient Synthesis of Benzimidazoles Catalyzed by Cobalt Nanocomposites on N-Doped Carbon

Synlett ◽  
2019 ◽  
Vol 30 (03) ◽  
pp. 319-324 ◽  
Author(s):  
Zhaozhan Wang ◽  
Tao Song ◽  
Yong Yang
Keyword(s):  
Functional Group ◽  
Direct Synthesis ◽  
Biologically Active ◽  
One Pot ◽  
Mild Conditions ◽  
Wide Range ◽  
High Yields

A one-pot direct synthesis of a wide range of biologically active benzimidazoles through coupling of phenylenediamines and aldehydes catalyzed by a highly recyclable nonnoble cobalt nanocomposite was developed. A broad set of benzimidazoles can be efficiently synthesized in high yields and with good functional-group tolerance under additive- and oxidant-free mild conditions. The catalyst can be easily recycled for successive uses, and the process permits gram-scale syntheses of benzimidazoles.

H2O as the Sole Hydrogen Source for Ni-Catalyzed Reduction of Alkenes

2019 ◽  
Author(s):  
Yichen Wu ◽  
Tao liu ◽  
Dongping Chen ◽  
Daoming Wang ◽  
Peng Wang
Keyword(s):  
Nickel Catalyst ◽  
Selective Hydrogenation ◽  
Functional Group ◽  
Catalytic Amount ◽  
Mild Conditions ◽  
Water As Solvent ◽  
Direct Hydrogenation ◽  
High Yields

Herein, we reported a nickel catalyzed hydrogenation of alkenes with water as the sole hydrogen source. Employing Zn as reductant and water as solvent in the presence of a catalytic amount of nickel catalyst led to direct hydrogenation of a series of electron-rich and electron-deficient alkenes in high yields. This protocol features unprecedented heterocycle and functional group tolerance under facile and mild conditions. Selective hydrogenation of the substrates containing additional reducible functionalities, such as alkenyl, alkynyl, chloride, ketone, and benzyl group etc, was also realized.

Michael Addition of Aryl Thiols to 3-(2,2,2-Trifluoroethylidene)Oxindoles under Catalyst-Free Conditions: The Rapid Synthesis of Sulfur-Containing Oxindole Derivatives

2018 ◽  
Vol 42 (4) ◽  
pp. 210-214
Author(s):  
Bo Chen ◽  
Jiaheng Lei ◽  
Junling Zhao
Keyword(s):  
Michael Addition ◽  
Room Temperature ◽  
Rapid Synthesis ◽  
Efficient Catalyst ◽  
Mild Conditions ◽  
Catalyst Free ◽  
Wide Range ◽  
High Yields ◽  
The Michael Addition ◽  
Sulfur Containing

A mild and efficient catalyst-free method for the rapid synthesis at room temperature of 3-thiomethylated oxindole derivatives has been achieved via the Michael addition of aryl thiols to ring and 1-substituted 3-(2,2,2-trifluoroethylidene)oxindoles in dichloromethane. The method was applicable to a wide range of thiols and variously substituted 3-(2,2,2-trifluoroethylidene)oxindoles under mild conditions as demonstrated by the synthesis in high yields with good diastereoselectivities of 30 3-thiomethylated oxindoles bearing a trifluoromethyl group.

s-Tetrazine: robust and green photo-organocatalyst for aerobic oxidation of N,N-disubstituted-hydroxylamines to nitrones

Synlett ◽  
2021 ◽  
Author(s):  
Jiyuan LYU ◽  
Tuan Le ◽  
Clémence Allain ◽  
Pierre Audebert ◽  
Geraldine Masson
Keyword(s):  
Oxidative Dehydrogenation ◽  
Aerobic Oxidation ◽  
Dehydrogenation Reaction ◽  
Mild Conditions ◽  
Wide Range ◽  
High Yields ◽  
Oxyallyl Cation

Efficient photocatalytic aerobic oxidative dehydrogenation reaction of N,N-disubstituted hydroxylamines to nitrones were developed with an in situ generated photocatalyst based on commercially available 3,6-dichlorotetrazine. This process affords a wide range of nitrones in high yields under mild conditions. In addition, an oxidative (3+3) cycloaddition between an oxyallyl cation precursor and a hydroxylamine was also developed.

H2O as the Sole Hydrogen Source for Ni-Catalyzed Reduction of Alkenes

2019 ◽  
Author(s):  
Yichen Wu ◽  
Tao liu ◽  
Dongping Chen ◽  
Daoming Wang ◽  
Peng Wang
Keyword(s):  
Nickel Catalyst ◽  
Selective Hydrogenation ◽  
Functional Group ◽  
Catalytic Amount ◽  
Mild Conditions ◽  
Water As Solvent ◽  
Direct Hydrogenation ◽  
High Yields

Herein, we reported a nickel catalyzed hydrogenation of alkenes with water as the sole hydrogen source. Employing Zn as reductant and water as solvent in the presence of a catalytic amount of nickel catalyst led to direct hydrogenation of a series of electron-rich and electron-deficient alkenes in high yields. This protocol features unprecedented heterocycle and functional group tolerance under facile and mild conditions. Selective hydrogenation of the substrates containing additional reducible functionalities, such as alkenyl, alkynyl, chloride, ketone, and benzyl group etc, was also realized.

scholarly journals Cobalt pincer complexes for catalytic reduction of nitriles to primary amines

2019 ◽  
Vol 9 (8) ◽  
pp. 1779-1783 ◽  
Author(s):  
Jacob Schneekönig ◽  
Bianca Tannert ◽  
Helen Hornke ◽  
Matthias Beller ◽  
Kathrin Junge
Keyword(s):  
Catalytic Reduction ◽  
Primary Amines ◽  
Pincer Complexes ◽  
Mild Conditions ◽  
Type Complex ◽  
High Yields ◽  
Hydrogenation Of Nitriles

An efficient cobalt pincer type complex catalyzes the hydrogenation of nitriles to amines under mild conditions with high yields.

Stereospecific, Palladium-catalyzed C(sp3)–H Alkenylation and Alkynylation of a Proline Derivative Enabled by 8-Aminoquinoline as a Directing Group

2020 ◽  
Author(s):  
Aleksandra Balliu ◽  
Aaltje Roelofje Femmigje Strijker ◽  
Michael Oschmann ◽  
Monireh Pourghasemi Lati ◽  
Oscar Verho
Keyword(s):  
Carboxylic Acid ◽  
Building Blocks ◽  
Wide Range ◽  
Palladium Catalyzed ◽  
Directing Group ◽  
High Yields ◽  
Vinyl Iodides ◽  
Initial Results

<p>In this preprint, we present our initial results concerning a stereospecific Pd-catalyzed protocol for the C3 alkenylation and alkynylation of a proline derivative carrying the well utilized 8‑aminoquinoline directing group. Efficient C–H alkenylation was achieved with a wide range of vinyl iodides bearing different aliphatic, aromatic and heteroaromatic substituents, to furnish the corresponding C3 alkenylated products in good to high yields. In addition, we were able show that this protocol can also be used to install an alkynyl group into the pyrrolidine scaffold, when a TIPS-protected alkynyl bromide was used as the reaction partner. Furthermore, two different methods for the removal of the 8-aminoquinoline auxiliary are reported, which can enable access to both <i>cis</i>- and <i>trans</i>-configured carboxylic acid building blocks from the C–H alkenylation products.</p>

Double Ring-Closing Approach for the Synthesis of 2,3,6,7-Substituted Anthracene Derivatives

2020 ◽  
Author(s):  
Birgit Meindl ◽  
Katharina Pfennigbauer ◽  
Berthold Stöger ◽  
Martin Heeney ◽  
Florian Glöcklhofer
Keyword(s):  
Wittig Reaction ◽  
Condensation Reaction ◽  
Synthetic Methods ◽  
Anthracene Derivative ◽  
Double Ring ◽  
Mild Conditions ◽  
Wide Range ◽  
Anthracene Derivatives

Anthracene derivatives have been used for a wide range of applications and many different synthetic methods for their preparation have been developed. However, despite continued synthetic efforts, introducing substituents in some positions has remained difficult. Here we present a method for the synthesis of 2,3,6,7-substituted anthracene derivatives, one of the most challenging anthracene substitution patterns to obtain. The method is exemplified by the preparation of 2,3,6,7-anthracenetetracarbonitrile and employs a newly developed, stable protected 1,2,4,5-benzenetetracarbaldehyde as the precursor. The precursor can be obtained in two scalable synthetic steps from 2,5-dibromoterephthalaldehyde and is converted into the anthracene derivative by a double intermolecular Wittig reaction under very mild conditions followed by a deprotection and intramolecular double ring-closing condensation reaction. Further modification of the precursor is expected to enable the introduction of additional substituents in other positions and may even enable the synthesis of fully substituted anthracene derivatives by the presented approach.<br>

Synthetic and Mechanistic Studies of a Versatile Heteroaryl Thioether Directing Group for Pd(II) Catalysis

2019 ◽  
Author(s):  
Andrew Romine ◽  
Kin Yang ◽  
Malkanthi Karunananda ◽  
Jason Chen ◽  
Keary Engle
Keyword(s):  
Mechanistic Studies ◽  
Salvianolic Acid ◽  
Wide Range ◽  
Computational Data ◽  
Synthetic Utility ◽  
Directing Group ◽  
High Yields ◽  
Julia Olefination ◽  
Reaction Progress Kinetic Analysis

A weakly coordinating monodentate heteroaryl thioether directing group has been developed for use in Pd(II) catalysis to orchestrate key elementary steps in the catalytic cycle that require conformational flexibility in a manner that is difficult to accomplish with traditional strongly coordinating directing groups. This benzothiazole thioether, (BT)S, directing group can be used to promote oxidative Heck reactivity of internal alkenes providing a wide range of products in moderate to high yields. To demonstrate the broad applicability of this directing group, arene C–H olefination was also successfully developed. Reaction progress kinetic analysis provides insights into the role of the directing group in each reaction, which is supplemented with computational data for the oxidative Heck reaction. Furthermore, this (BT)S directing group can be transformed into a number of synthetically useful functional groups, including a sulfone for Julia olefination, allowing it to serve as a “masked olefin” directing group in synthetic planning. In order to demonstrate this synthetic utility, natural products (+)-salvianolic acid A and salvianolic acid F are formally synthesized using the (BT)S directed C–H olefination as the key step.

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