scholarly journals Base Metal Catalysts for Deoxygenative Reduction of Amides to Amines

Catalysts ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 490 ◽  
Author(s):  
Andrey Khalimon ◽  
Kristina Gudun ◽  
Davit Hayrapetyan
Keyword(s):  
Base Metal ◽  
Precious Metals ◽  
Building Blocks ◽  
Metal Catalysts ◽  
Environmentally Benign ◽  
Attractive Alternative ◽  
Catalytic Systems ◽  
Amide Carbonyl ◽  
Amide Carbonyl Group ◽  
Metal Catalyzed

The development of efficient methodologies for production of amines attracts significant attention from synthetic chemists, because amines serve as essential building blocks in the synthesis of many pharmaceuticals, natural products, and agrochemicals. In this regard, deoxygenative reduction of amides to amines by means of transition-metal-catalyzed hydrogenation, hydrosilylation, and hydroboration reactions represents an attractive alternative to conventional wasteful techniques based on stoichiometric reductions of the corresponding amides and imines, and reductive amination of aldehydes with metal hydride reagents. The relatively low electrophilicity of the amide carbonyl group makes this transformation more challenging compared to reduction of other carbonyl compounds, and the majority of the reported catalytic systems employ precious metals such as platinum, rhodium, iridium, and ruthenium. Despite the application of more abundant and environmentally benign base metal (Mn, Fe, Co, and Ni) complexes for deoxygenative reduction of amides have been developed to a lesser extent, such catalytic systems are of great importance. This review is focused on the current achievements in the base-metal-catalyzed deoxygenative hydrogenation, hydrosilylation, and hydroboration of amides to amines. Special attention is paid to the design of base metal catalysts and the mechanisms of such catalytic transformations.

Base-Metal-Catalyzed Olefin Isomerization Reactions

Synthesis ◽  
2019 ◽  
Vol 51 (06) ◽  
pp. 1293-1310 ◽  
Author(s):  
Qiang Liu ◽  
Xufang Liu ◽  
Bin Li
Keyword(s):  
Base Metal ◽  
Precious Metals ◽  
Economic Transformation ◽  
Environmentally Benign ◽  
Isomerization Reaction ◽  
Olefin Isomerization ◽  
Earth Abundant ◽  
Wide Availability ◽  
Benign Nature ◽  
Metal Catalyzed

The catalytic olefin isomerization reaction is a highly efficient and atom-economic transformation in organic synthesis that has attracted tremendous attention both in academia and industry. Recently, the development of Earth-abundant metal catalysts has received growing interest owing to their wide availability, sustainability, and ­environmentally benign nature, as well as the unique properties of non-precious metals. This review provides an overview of a broad range of base-metal-catalyzed olefin isomerization reactions categorized ­according to their different reaction mechanisms.1 Introduction2 Base-Metal-Catalyzed Olefin Isomerization Reactions3 Base-Metal-Catalyzed Cycloisomerization Reactions4 Conclusion

scholarly journals Transition-Metal-Catalyzed Alkenyl sp2 C–H Activation: A Short Account

Synthesis ◽  
2019 ◽  
Vol 51 (05) ◽  
pp. 1049-1062 ◽  
Author(s):  
Manikantha Maraswami ◽  
Teck-Peng Loh
Keyword(s):  
Transition Metal ◽  
Scientific Community ◽  
Chemical Properties ◽  
Building Blocks ◽  
Metal Catalysts ◽  
Transition Metal Catalysts ◽  
The Other ◽  
Short Account ◽  
Other Hand ◽  
Metal Catalyzed

Alkenes are ubiquitous in Nature and their functionalization continues to attract attention from the scientific community. On the other hand, activation of alkenyl sp2 C–H bonds is challenging due to their chemical properties. In this short account, we elucidate, discuss and describe the utilization of transition-metal catalysts in alkene activation and provide useful strategies to synthesize organic building blocks in an efficient and sustainable manner.1 Introduction2 Breakthrough3 Controlling E/Z, Z/E Selectivity3.1 Esters and Amides as Directing Groups3.2 The Chelation versus Non-Chelation Concept4 Other Alkene Derivatives5 Intramolecular C–H Activation6 Conclusion and Future Projects

Imidates: an emerging synthon for N-heterocycles

2019 ◽  
Vol 17 (46) ◽  
pp. 9829-9843 ◽  
Author(s):  
Rima Thakur ◽  
Yogesh Jaiswal ◽  
Amit Kumar
Keyword(s):  
Base Metal ◽  
Building Blocks ◽  
Recent Application ◽  
Acid Base ◽  
Reaction Conditions ◽  
Metal Catalyzed

This review highlights the recent application of imidates as building blocks for the synthesis of saturated and un-saturated N-heterocycles via C–N annulation reactions under acid/base/metal-catalyzed/radical-mediated reaction conditions.

scholarly journals Protein-engineering of an amine transaminase for the stereoselective synthesis of a pharmaceutically relevant bicyclic amine

2016 ◽  
Vol 14 (43) ◽  
pp. 10249-10254 ◽  
Author(s):  
Martin S. Weiß ◽  
Ioannis V. Pavlidis ◽  
Paul Spurr ◽  
Steven P. Hanlon ◽  
Beat Wirz ◽  
...  
Keyword(s):  
Transition Metal ◽  
Protein Engineering ◽  
Asymmetric Synthesis ◽  
Stereoselective Synthesis ◽  
Environmentally Benign ◽  
Attractive Alternative ◽  
P Application ◽  
Transition Metal Catalyzed ◽  
Prochiral Ketones ◽  
Metal Catalyzed

Application of amine transaminases (ATAs) for stereoselective amination of prochiral ketones represents an environmentally benign and economically attractive alternative to transition metal catalyzed asymmetric synthesis.

Transition-Metal-Free Functionalization of Saturated and Unsaturated Amines to Bioactive Alkaloids Mediated by Sodium Chlorite

Synlett ◽  
2020 ◽  
Author(s):  
Fernando Sartillo-Piscil ◽  
Julio Romero-Ibañez ◽  
Lilia Fuentes
Keyword(s):  
Transition Metal ◽  
Precious Metals ◽  
Extraction Process ◽  
Metal Catalysts ◽  
Transition Metal Catalysts ◽  
Sodium Chlorite ◽  
Chemical Transformations ◽  
Metal Free ◽  
Cyclic Amines ◽  
Metal Catalyzed

AbstractNew approaches to the synthesis of alkaloids through the straightforward functionalization of C(sp3)–H and C(sp2)=C(sp2) bonds of simple five- and six-membered-ring N-heterocycles are highlighted. The direct functionalization of pre-existing N-heterocycles to advanced alkaloids intermediates is a chemical operation that commonly requires the intervention of transition or precious metals. Regardless the inherent unwanted waste production, the high economical cost of many transition-metal catalysts limits their use globally. Here, we account our efforts directed toward the synthesis of bioactive alkaloids under an economic and ecological fashion by using NaClO2 as the key activating or oxidizing reagent that substitutes the use of transition-metal catalysts. While undesired metal wastes are collected during the extraction process of a transition-metal-catalyzed reaction, innocuous NaCl is the commonly product waste when NaClO2 is employed in our chemical transformations. Beginning with the synthesis of 2,3-epoxyamides from allyl amines, we concluded with the functionalization of multiple and remote C(sp3)–H and C(sp3)–C(sp3) bonds in piperidine rings that enabled the preparation of important bioactive alkaloids. For the latter functionalization, a precise amount of co-oxidant reagent (NaOCl) and radical 2,2,6,6-tetramethylpiperidinyloxy (TEMPO) were needed.1 Introduction2 Direct Chemical Method for Preparing 2,3-Epoxyamides3 Dual C(sp3)–H Oxidation of Cyclic Amines to 3‑Alkoxyamine Lac­tams4 Electrochemical Deamination of 3-Alkoxyamine Lactams5 Direct C–H Oxidation of Piperazines and Morpholines to 2,3-Diketopiperazines and 3-Morpholinones, Respectively6 Transition-Metal-Free Triple C–H Oxidation7 Deconstructive Lactamization of Piperidines8 Conclusion

scholarly journals Catalytic (de)hydrogenation promoted by non-precious metals – Co, Fe and Mn: recent advances in an emerging field

2018 ◽  
Vol 47 (4) ◽  
pp. 1459-1483 ◽  
Author(s):  
Georgy A. Filonenko ◽  
Robbert van Putten ◽  
Emiel J. M. Hensen ◽  
Evgeny A. Pidko
Keyword(s):  
Base Metal ◽  
Precious Metals ◽  
Metal Catalysts ◽  
Recent Advances ◽  
Fe And Mn ◽  
Remarkable Progress ◽  
Made In

This review is aimed at introducing the remarkable progress made in the last three years in the development of base metal catalysts for hydrogenations and dehydrogenative transformations.

The Mechanism of the Transition Metal-catalyzed Reaction of 1,1′-Carbonyldipyrazoles with Aldehydes and Ketones

1974 ◽  
Vol 52 (13) ◽  
pp. 2367-2374 ◽  
Author(s):  
L. K. Peterson ◽  
E. Kiehlmann ◽  
A. R. Sanger ◽  
K. I. Thé
Keyword(s):  
Carbon Dioxide ◽  
Metal Ion ◽  
Substituent Effects ◽  
Amide Bond ◽  
Reaction Conditions ◽  
Aldehydes And Ketones ◽  
Amide Carbonyl ◽  
Amide Carbonyl Group ◽  
Metal Catalyzed ◽  
Metal Ion Exchange

The metal-catalyzed reaction of 1,1′-carbonyldipyrazoles with aldehydes or ketones to give 1,1′-alkylidenedipyrazoles and carbon dioxide, the latter being derived from the amide carbonyl group as shown by labeling experiments, is sensitive to electronic and to steric substituent effects. Under comparable reaction conditions, 1,1′-carbonyldiimidazole, N-acetylpyrazole, and 1-pyrazole-N,N-diethylcarbonamide do not react with acetone while pyrazole-1-carbo(N′-phenylhydrazide) yields an anilino isocyanate dimer. These results are interpreted in terms of a mechanism that involves coordination of the metal ion at the 2,2′-nitrogen atoms of the pyrazole rings and heterolytic cleavage of an amide bond, followed by formation of a carbamate intermediate, decarboxylation, and metal ion exchange. Unsymmetrically substituted 1,1′-carbonyldipyrazoles were found to equilibrate thermally with their respective symmetrical analogs by an intermolecular exchange mechanism.

Enantioselective direct, base-free hydrogenation of ketones by a manganese amido complex of a homochiral, unsymmetrical P-N-P’ ligand

2021 ◽  
Author(s):  
Chris S. G. Seo ◽  
Brian Tsz Ho Tsui ◽  
Matthew Viktor Gradiski ◽  
Samantha A. M. Smith ◽  
Robert H Morris
Keyword(s):  
Base Metal ◽  
Metal Catalysts ◽  
Environmentally Benign ◽  
Great Promise ◽  
Homogeneous Hydrogenation ◽  
Hydrogenation Catalysis

The use of manganese in homogeneous hydrogenation catalysis has been a recent focus in the pursuit of more environmentally benign base metal catalysts. It has great promise with its unique...

Designed pincer ligands supported Co(II)-based catalysts for dehydrogenative activation of alcohols: Studies on N-alkylation of amines, -alkylation of ketones and synthesis of quinolines

2021 ◽  
Author(s):  
Anshu Singh ◽  
Ankur Maji ◽  
Mayank Joshi ◽  
Angshuman Roychoudhury ◽  
Kaushik Ghosh
Keyword(s):  
Base Metal ◽  
Metal Catalysts ◽  
Pincer Ligands ◽  
Activation Of Alcohols

Base-metal catalysts Co1, Co2 and Co3 were synthesized from designed pincer ligands L1, L2 and L3 having NNN donor atoms respectively. Co1, Co2 and Co3 were characterized by IR, UV–Vis....

scholarly journals Transition metal-catalyzed organic reactions in undivided electrochemical cells

2021 ◽  
Author(s):  
Cong Ma ◽  
Ping Fang ◽  
Dong Liu ◽  
Ke-Jin Jiao ◽  
Pei-Sen Gao ◽  
...  
Keyword(s):  
Transition Metal ◽  
Research Area ◽  
Metal Catalysts ◽  
Organic Reactions ◽  
Electrochemical Cells ◽  
Organic Electrochemistry ◽  
Transition Metal Catalyzed ◽  
Metal Catalyzed

Abstract: Transition metal-catalyzed organic electrochemistry is a rapidly growing research area owing in part of the ability of metal catalysts to alter the selectivity of a given transformation. This conversion...

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