scholarly journals Isoquinolone Synthesis via Zn(OTf)2-Catalyzed Aerobic Cyclocondensation of 2-(1-Alkynyl)-benzaldehydes with Arylamines

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 683 ◽  
Author(s):  
Dost Muhammad Khan ◽  
Ruimao Hua
Keyword(s):  
Lewis Acid ◽  
Catalyst System ◽  
Oxygen Atmosphere ◽  
High Yields

A zinc(II) triflate-catalyzed cyclocondensation of ortho-alkynylbenzaldehydes with arylamines in the presence of base under an oxygen atmosphere affording isoquinolones in good to high yields has been developed. The advantages of the present catalyst system include the use of an air-stable and cheap commercially available Lewis acid as the catalyst, high atom utilization and easily available starting materials.

Metathetical Degradation and Depolymerization of Unsaturated Polymers

1997 ◽  
Vol 70 (3) ◽  
pp. 519-529 ◽  
Author(s):  
J. C. Marmo ◽  
K. B. Wagener
Keyword(s):  
Molecular Weight ◽  
Transition Metal ◽  
Catalytic System ◽  
Lewis Acid ◽  
Catalyst System ◽  
Metal Catalysts ◽  
Transition Metal Catalysts ◽  
Side Reactions

Abstract The employment of transition metal catalysts has been a viable route in the degradation and depolymerization of unsaturated polymers. Initially, unsaturated polymers were degraded with a catalytic system containing a transition metal and a Lewis acid cocatalyst (WCl6/SnBu4). Degradation chemistry was effective in reducing the molecular weight of the polymer, however, the classical catalyst system induces side reactions which generates ill-defined products. These side reactions were obviated by using a preformed alkylidene without a Lewis acid cocatalyst, and perfectly difunctional telechelics were synthesized.

Hypervalent Iodine-Mediated Beckmann Rearrangement of Ketoximes

Synlett ◽  
2018 ◽  
Vol 29 (11) ◽  
pp. 1465-1468 ◽  
Author(s):  
Tomohiro Maegawa ◽  
Yasuyoshi Miki ◽  
Ryohei Oishi ◽  
Kazutoshi Segi ◽  
Hiromi Hamamoto ◽  
...  
Keyword(s):  
Lewis Acid ◽  
Beckmann Rearrangement ◽  
Hypervalent Iodine ◽  
Mild Conditions ◽  
High Yields

We developed a Beckmann rearrangement employing hypervalent iodine reagent under mild conditions. The reaction of ketoxime with hypervalent iodine afforded the corresponding ketone, but premixing of hypervalent iodine and a Lewis acid was effective for promoting Beckmann rearrangement. Aromatic and aliphatic ketoximes were converted into their corresponding amides in good to high yields.

A Dual Functional Tuneable‐Lewis Acid/Sulfur Scavenging Catalyst System for Alpha Olefin Oligomerization

2019 ◽  
Vol 4 (36) ◽  
pp. 10688-10693 ◽  
Author(s):  
Bojja Ramachandrarao ◽  
Kottari Naresh ◽  
Ashoutosh Panday ◽  
Nettem Venkateswarlu Choudary
Keyword(s):  
Lewis Acid ◽  
Catalyst System ◽  
Dual Functional ◽  
Alpha Olefin ◽  
Olefin Oligomerization

Efficient Synthesis of Diarylmethylamines via Lewis Acid Catalyzed Friedel–Crafts Reactions of Donor–Acceptor Aziridines with N,N-Dialkylanilines

Synthesis ◽  
2019 ◽  
Vol 52 (02) ◽  
pp. 281-289
Author(s):  
Yerin Kim ◽  
Yong Il Kwon ◽  
Sung-Gon Kim
Keyword(s):  
Lewis Acid ◽  
Efficient Synthesis ◽  
Broad Scope ◽  
Donor Acceptor ◽  
Acid Catalyzed ◽  
High Yields

A method for efficient and mild synthesis of diarylmethylamine scaffold, via Lewis acid catalyzed Friedel–Crafts reaction of donor­–acceptor aziridines with N,N-dialkylanilines to afford a biologically important diarylmethylamine derivatives in high yields (up to 88%), is presented. This reaction is suitable for the synthesis of various diarylmethylamine derivatives and has a broad scope for electron-rich arenes, including dimethoxybenzene.

scholarly journals Decarbonylation through Aldehydic C–H Bond Cleavage by a Cationic Iridium Catalyst

Synlett ◽  
2019 ◽  
Vol 30 (08) ◽  
pp. 972-976 ◽  
Author(s):  
Tomohiko Shirai ◽  
Kazuki Sugimoto ◽  
Masaya Iwasaki ◽  
Ryuki Sumida ◽  
Harunori Fujita ◽  
...  
Keyword(s):  
Bond Cleavage ◽  
Catalyst System ◽  
Mild Conditions ◽  
Iridium Catalyst ◽  
Reaction Proceeds ◽  
High Yields

We report the decarbonylation of aldehydes through an aldehydic C–H bond cleavage catalyzed by a cationic iridium/bisphosphine catalyst. The reaction proceeds under relatively mild conditions to give the corresponding hydrocarbon products in moderate to high yields. In addition, this cationic iridium catalyst system can be applied to an asymmetric hydroacylation of ketones.

scholarly journals Copper nanoparticles on controlled pore glass (CPG) as highly efficient heterogeneous catalysts for “click reactions”

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Abdolrahim A. Rafi ◽  
Ismail Ibrahem ◽  
Armando Córdova
Keyword(s):  
Copper Nanoparticles ◽  
Heterogeneous Catalysts ◽  
Catalyst System ◽  
Terminal Alkynes ◽  
Click Reactions ◽  
Dipolar Cycloadditions ◽  
Organic Azides ◽  
Controlled Pore Glass ◽  
Pore Glass ◽  
High Yields

AbstractWe herein report that supported copper nanoparticles (CuNPs) on commercially available controlled pore glass (CPG), which exhibit high mechanical, thermal and chemical stability as compared to other silica-based materials, serve as a useful heterogeneous catalyst system for 1,3-dipolar cycloadditions (“click” reactions) between terminal alkynes and organic azides under green chemistry conditions. The supported CuNPs-CPG catalyst exhibited a broad substrate scope and gave the corresponding triazole products in high yields. The CuNPs-CPG catalyst exhibit recyclability and could be reuced multiple times without contaminating the products with Cu.

Lewis Acid-Catalyzed Rearrangement of Fluoroalkylated Propargylic Alcohols: An Alternative Approach to β-Fluoroalkyl-α,β-enones

Synlett ◽  
2019 ◽  
Vol 30 (03) ◽  
pp. 356-360 ◽  
Author(s):  
Manickavasakam Ramasamy ◽  
Hui-Chang Lin ◽  
Sheng-Chu Kuo ◽  
Min-Tsang Hsieh
Keyword(s):  
Lewis Acid ◽  
Propargylic Alcohols ◽  
Alternative Approach ◽  
Acid Catalyzed ◽  
High Yields ◽  
High Stereoselectivity

A practical Lewis acid-catalyzed Meyer–Schuster rearrangement of fluoroalkylated propargylic alcohols, leading to a series of β-fluoroalkyl-α,β-enones, is developed. The methodology reported herein features moderate to high yields and high stereoselectivity in the synthesis of β-alkyl-β-fluoroalkyl-α,β-enones.

scholarly journals Reactions of biologically inspired hydride sources with B(C 6 F 5 ) 3

2017 ◽  
Vol 375 (2101) ◽  
pp. 20170009 ◽  
Author(s):  
Lewis C. Wilkins ◽  
Nicolò Santi ◽  
Louis Y. P. Luk ◽  
Rebecca L. Melen
Keyword(s):  
Carboxylic Acid ◽  
Recent Work ◽  
Lewis Acid ◽  
The Other ◽  
Disproportionation Reaction ◽  
Transfer Hydrogenation ◽  
Acid Moiety ◽  
Biologically Inspired ◽  
Strong Lewis Acid ◽  
High Yields

The combination of 1-benzyl-1,4-dihydropyridines with the strong Lewis acid, B(C 6 F 5 ) 3 , generates a stable pyridinium borohydride species in high yields (94%) in as little as 10 min. This use of biologically inspired hydride sources further builds on the recent work of new hydride donors in the formation of borohydrides. When functionalizing the dihydropyridine with an amide or carboxylic acid moiety, a disproportionation reaction composed of a series of protonation/reduction steps is observed upon the addition of B(C 6 F 5 ) 3 . As a result, one equivalent of dihydropyridine undergoes net hydrogenation, whereas the other is dehydrogenated yielding the pyridinium counterpart in a transfer hydrogenation-type mechanism. This article is part of the themed issue ‘Frustrated Lewis pair chemistry’.

scholarly journals A New Method for the Synthesis of 2-Substituted Benzoxazoles from 2-Nitrophenol Derivatives and Aldehydes  

2021 ◽  
Vol 31 (3) ◽  
pp. 43-46
Keyword(s):  
Biological Activities ◽  
Catalyst System ◽  
Biologically Active ◽  
New Method ◽  
Redox Catalyst ◽  
High Pressure High Temperature ◽  
One Step ◽  
High Yields ◽  
Strong Acids ◽  
Single Reaction

Benzoxazole derivatives are one of the compounds with many interesting biological activities. Conventional methods are often performed under complex conditions using strong acids, expensive metal catalysts, requiring high pressure, high temperature, and under microwave irradiation. In this study, we reported a new method of benzoxazole synthesis with redox catalyst using FeCl3.6H2O and sulfur. This is a suitable, efficient, readily available and environmentally friendly catalyst system for redox and condensation reactions in one step at 100 oC. Applying this new method, we have synthesized eight 2-arylbenzoxazole derivatives with high yields (calculated according to 2-nitrophenol). This research is an important step forward in the synthesis of biologically active compounds containing the benzoxazole framework from readily available starting materials in a single reaction.

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