scholarly journals Transformation of alcohols to esters promoted by hydrogen bonds using oxygen as the oxidant under metal-free conditions

2018 ◽  
Vol 4 (10) ◽  
pp. eaas9319 ◽  
Author(s):  
Mingyang Liu ◽  
Zhanrong Zhang ◽  
Huizhen Liu ◽  
Zhenbing Xie ◽  
Qingqing Mei ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Aliphatic Alcohols ◽  
Hydroxyl Groups ◽  
Acetate Anion ◽  
One Pot ◽  
Benzylic Alcohols ◽  
Metal Free ◽  
Acidic Proton ◽  
Basic Ionic Liquid ◽  
High Yields

One-pot oxidative transformation of alcohols into esters is very attractive, but metal-based catalysts are used in the reported routes. We discovered that the basic ionic liquid 1-ethyl-3-methylimidazolium acetate ([EMIM] OAc) could effectively catalyze this kind of reaction using O2 as an oxidant without any other catalysts or additives. The oxidative self-esterification of benzylic alcohols or aliphatic alcohols and cross-esterification between benzyl alcohols and aliphatic alcohols could all be achieved with high yields. Detailed study revealed that the cation with acidic proton and basic acetate anion could simultaneously form multiple hydrogen bonds with the hydroxyl groups of the alcohols, which catalyzed the reaction very effectively. As far as we know, this is the first work to carry out this kind of reaction under metal-free conditions.

Metal-free one-pot α -benzoxylation of benzylic alcohols with acids or aldehydes

2018 ◽  
Vol 59 (4) ◽  
pp. 368-371 ◽  
Author(s):  
Yefu Zhu ◽  
Yong Zheng ◽  
Weibin Song ◽  
Bole Wei ◽  
Lijiang Xuan
Keyword(s):  
One Pot ◽  
Benzylic Alcohols ◽  
Metal Free

scholarly journals Pentafluoropropionic Acid: An Efficient and Metal-Free Catalyst for the One-Pot Synthesis of Tetrahydrobenzo[b]pyran Derivatives

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Naser Montazeri ◽  
Taghva Noghani ◽  
Mona Ghorchibeigy ◽  
Rozita Zoghi
Keyword(s):  
Reaction Time ◽  
Aromatic Aldehyde ◽  
One Pot ◽  
Short Reaction Time ◽  
Metal Free ◽  
One Pot Synthesis ◽  
Three Component Reaction ◽  
The One ◽  
High Yields

Pentafluoropropionic acid (PFPA) efficiently catalyzes the one-pot, three-component reaction of aromatic aldehyde, malononitrile, and dimedone to yield tetrahydrobenzo[b]pyran derivatives in high yields. This method is of great value because of its easy processing, short reaction time, environmentally, and high yields.

scholarly journals (C7H6NS)2[Nb6Cl18]·2C4H8O: first niobium cluster with an N,S-heterocyclic cation

IUCrData ◽  
2018 ◽  
Vol 3 (12) ◽  
Author(s):  
Eric Sperlich ◽  
Martin Köckerling
Keyword(s):  
Hydrogen Bonds ◽  
Title Compound ◽  
Room Temperature ◽  
High Yield ◽  
Cluster Compound ◽  
One Pot ◽  
Cluster Precursor ◽  
Acidic Proton ◽  
Very High

The title compound bis(benzothiazolium) dodeca-μ-chlorido-hexachlorido-octahedro-hexaniobium(12 Nb—Nb) tetrahydrofuran disolvate, (C7H6NS)2[Nb6Cl18]·2C4H8O or (HBTh)2[Nb6Cl18]·2THF, is the first known niobium cluster compound to contain an N,S-heterocyclic cation. The synthesis takes place within a few hours as an one-pot reaction at room temperature of the cluster precursor compound [Nb6Cl14(H2O)4]·4H2O with SOCl2 in the presence of BTh (benzothiazole) in very high yield. The stabilization of the acidic proton of the cation is achieved by the use of tetrahydrofuran as a co-solvent and by the formation of hydrogen bonds.

scholarly journals Metal-free syntheses of new azocines via addition reactions of enaminones with acenaphthoquinone followed by oxidative cleavages of the corresponding vicinal diols

RSC Advances ◽  
2020 ◽  
Vol 10 (35) ◽  
pp. 20552-20557
Author(s):  
S. Hekmat Mousavi ◽  
Mohammad Reza Mohammadizadeh ◽  
Satoru Arimitsu ◽  
Dariush Saberi ◽  
Samira Poorsadeghi ◽  
...  
Keyword(s):  
Periodic Acid ◽  
Addition Reactions ◽  
Reaction Conditions ◽  
One Pot ◽  
Metal Free ◽  
Vicinal Diols ◽  
High Yields

One-pot metal-free periodic acid-mediated syntheses of azocine rings with high yields under mild reaction conditions via the addition reactions of enaminones and acenaphthoquinone.

One-pot metal-free synthesis of highly substituted pyrroles from 2-acetyl-3-methylene-1,4-dicarbonyl compounds and primary amines via TBHP and activated carbon oxidative aromatization of dihydropyrrole

RSC Advances ◽  
2014 ◽  
Vol 4 (29) ◽  
pp. 15007-15010 ◽  
Author(s):  
Wei Yang ◽  
Yu Zhou ◽  
Haifeng Sun ◽  
Lei Zhang ◽  
Fei Zhao ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Michael Addition ◽  
Primary Amines ◽  
Cascade Process ◽  
One Pot ◽  
Metal Free ◽  
Oxidative Aromatization ◽  
Substituted Pyrroles ◽  
Substrate Tolerance ◽  
High Yields

A metal-free cascade process for the synthesis of highly substituted pyrroles with high yields and broad substrate tolerance via enamine, aza-Michael addition and TBHP, activated carbon oxidative aromatization is reported.

Metal-Free Photoinduced Hydroalkylation Cascade Enabled by an Electron-Donor-Acceptor Complex

2020 ◽  
Author(s):  
José Tiago Menezes Correia ◽  
Gustavo Piva da Silva ◽  
Camila Menezes Kisukuri ◽  
Elias André ◽  
Bruno Pires ◽  
...  
Keyword(s):  
Electron Donor ◽  
Functional Group ◽  
Photoexcited Electron ◽  
One Pot ◽  
Quaternary Centers ◽  
Metal Free ◽  
Acceptor Complex ◽  
Catalyst Free ◽  
Donor Acceptor ◽  
Radical Cascade

A metal- and catalyst-free photoinduced radical cascade hydroalkylation of 1,7-enynes has been disclosed. The process is triggered by a SET event involving a photoexcited electron-donor-aceptor complex between NHPI ester and Hantzsch ester, which decomposes to afford a tertiary radical that is readily trapped by the enyne. <a>The method provides an operationally simple, robust and step-economical approach to the construction of diversely functionalized dihydroquinolinones bearing quaternary-centers. A sequential one-pot hydroalkylation-isomerization approach is also allowed giving access to a family of quinolinones. A wide substrate scope and high functional group tolerance was observed in both approaches</a>.

Metal-Free Photoredox-Catalyzed C–H/C–H Coupling of Arenes Enabled by Interrupted Pummerer Activation

2019 ◽  
Author(s):  
Miles Aukland ◽  
Mindaugas Šiaučiulis ◽  
Adam West ◽  
Gregory Perry ◽  
David Procter
Keyword(s):  
Natural Product ◽  
Selective Reduction ◽  
Cross Coupling ◽  
One Pot ◽  
Complex Molecules ◽  
Pummerer Reaction ◽  
Metal Free ◽  
Bond Forming ◽  
Coupling Partner ◽  
Bioactive Natural Product

<p>Aryl–aryl cross-coupling constitutes one of the most widely used procedures for the synthesis of high-value materials, ranging from pharmaceuticals to organic electronics and conducting polymers. The assembly of (hetero)biaryl scaffolds generally requires multiple steps; coupling partners must be functionalized before the key bond-forming event is considered. Thus, the development of selective C–H arylation processes in arenes, that side-step the need for prefunctionalized partners, is crucial for streamlining the construction of these key architectures. Here we report an expedient, one-pot assembly of (hetero)biaryl motifs using photocatalysis and two non-prefunctionalized arene partners. The approach is underpinned by the activation of a C–H bond in an arene coupling partner using the interrupted Pummerer reaction. A unique pairing of the organic photoredox catalyst and the intermediate dibenzothiophenium salts enables highly selective reduction in the presence of sensitive functionalities. The utility of the metal-free, one-pot strategy is exemplified by the synthesis of a bioactive natural product and the modification of complex molecules of societal importance.</p>

An Expeditious One-Pot Three-Component Synthesis of 4-Aryl-3,4-dihydrobenzo[g] quinoline-2,5,10(1H)-triones under Green Conditions

2020 ◽  
Vol 23 (23) ◽  
pp. 2626-2634
Author(s):  
Saiedeh Kamalifar ◽  
Hamzeh Kiyani
Keyword(s):  
Reaction Medium ◽  
Meldrum's Acid ◽  
Meldrum’S Acid ◽  
One Pot ◽  
One Pot Synthesis ◽  
Substituted Benzaldehydes ◽  
High Yields ◽  
First Time ◽  
Green Conditions

: An efficient and facial one-pot synthesis of 4-aryl-3,4-dihydrobenzo[g]quinoline- 2,5,10(1H)-triones was developed for the first time. The process proceeded via the three-component cyclocondensation of 2-amino-1,4-naphthoquinone with Meldrum’s acid and substituted benzaldehydes under green conditions. The fused 3,4-dihydropyridin-2(1H)- one-ring naphthoquinones have been synthesized with good to high yields in refluxing ethanol as a green reaction medium. This protocol is simple and effective as well as does not involve the assistance of the catalyst, additive, or hazardous solvents.

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