scholarly journals Traceless Directing Groups in Sustainable Metal-Catalyzed C–H Activation

Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 554
Author(s):  
Athanasios Zarkadoulas ◽  
Ioanna Zgouleta ◽  
Nikolaos V. Tzouras ◽  
Georgios C. Vougioukalakis
Keyword(s):  
Copper Catalysts ◽  
Chemical Transformations ◽  
Atom Economy ◽  
One Pot ◽  
Cobalt Nickel ◽  
Structure Activity ◽  
Transition Metal Salts ◽  
Metal Catalyzed ◽  
High Yields ◽  
Work Done

Sustainable transformations towards the production of valuable chemicals constantly attract interest, both in terms of academic and applied research. C–H activation has long been scrutinized in this regard, given that it offers a straightforward pathway to prepare compounds of great significance. In this context, directing groups (DG) have paved the way for chemical transformations that had not been achievable using traditional reactions. Few steps, high yields, selectivity and activation of inert substrates are some of the invaluable assets of directed catalysis. Additionally, the employment of traceless directing groups (TDG) greatly improves and simplifies this strategy, enabling the realization of multi-step reactions in one-pot, cascade procedures. Cheap, abundant, readily available transition metal salts and complexes can catalyze a plethora of reactions employing TDGs, usually under low catalyst loadings—rarely under stoichiometric amounts, leading in greater atom economy and milder conditions with increased yields and step-economy. This review article summarizes all the work done on TDG-assisted catalysis with manganese, iron, cobalt, nickel, or copper catalysts, and discusses the structure-activity relationships observed, by presenting the catalytic pathways and range of transformations reported thus far.

Novel One-pot Synthesis of Pyranocarbazole Derivatives via an Isocyanide-based Three-component Reaction

2020 ◽  
Vol 17 ◽  
Author(s):  
Visarapu Malathi ◽  
Pedavenkatagari Narayana Reddy ◽  
Pannala Padmaja
Keyword(s):  
Efficient Method ◽  
Atom Economy ◽  
Reaction Conditions ◽  
One Pot ◽  
Catalyst Free ◽  
One Pot Synthesis ◽  
Three Component Reaction ◽  
High Yields

Abstract:: An efficient method has been developed for the synthesis of new pyrano[3,2-c] and pyrano[3,2-a]carbazole de-rivatives via a three component reaction of 4-hydroxycarbazole or 2-hydroxycarbazole, isocyanides, and dialkylacetylenedi-carboxylates. Noteworthy features of this protocol include mild reaction conditions, catalyst-free, high atom-economy and high yields.

scholarly journals Highly Diastereoselective Synthesis of Tetrahydroquinoline Derivatives via [4 + 2] Annulation of Ortho-Tosylaminophenyl-Substituted Para-Quinone Methides and Cyanoalkenes

2021 ◽  
Vol 9 ◽  
Author(s):  
Taiwei Dong ◽  
Peifeng Wei ◽  
Min Li ◽  
Feng Gao ◽  
Yuan Qin
Keyword(s):  
Biologically Active ◽  
Structural Motif ◽  
Diastereoselective Synthesis ◽  
Atom Economy ◽  
Quinone Methides ◽  
One Pot ◽  
Reaction Performance ◽  
High Yields ◽  
Active Natural

As a privileged structural motif, tetrahydroquinoline skeletons widely exist in biologically active natural products and pharmaceuticals. In this protocol, a highly diastereoselective [4 + 2] annulation of ortho-tosylaminophenyl-substituted p-QMs and cyanoalkenes to construct tetrahydroquinoline derivatives has been successfully achieved. This strategy proceeds efficiently under mild condition, offering straightforward route to a variety of 4-aryl-substituted tetrahydroquinolines with high yields, excellent diastereoselectivities, broad functional group tolerance as well as gram-scale capacity. Moreover, a one-pot reaction sequence utilizing in situ generated p-QMs under the similar condition to build tetrahydroquinoline framework is smoothly conducted with good reaction performance as well as step and atom economy.

Synthesis of New 5-amino-7-(aryl)-1,2,3,7-tetrahydro-8-nitroimidazo[1,2-a]pyridine- 6-carboxamide and 6-amino-2,3,4,8-tetrahydro-9-nitro-8-(aryl)-1H-pyrido[1,2- a]pyrimidine-7-carboxamide Derivatives

2018 ◽  
Vol 15 (7) ◽  
pp. 982-988 ◽  
Author(s):  
Fahimeh S. Hosseini ◽  
Mohammad Bayat
Keyword(s):  
Aromatic Aldehydes ◽  
Chromatographic Technique ◽  
Efficient Synthesis ◽  
Atom Economy ◽  
Reaction Conditions ◽  
One Pot ◽  
Synthetic Routes ◽  
High Yields ◽  
Work Up ◽  
Optimal Reaction

Aim and Objectives: Development of simple synthetic routes for widely used organic compounds from readily available reagents is one of the major tasks in organic chemistry. Therefore, new approaches for increasing the molecular diversity of simple starting materials, are needed. Herein, an efficient synthesis of imidazo[1,2-a]pyridine, pyrido[1,2-a]pyrimidine and pyrido[1,2-a][1,3]diazepine derivatives is described. Materials and Methods: A one-pot, multi-component reaction of nitro ketene aminal derived from the addition of various 1,n-diamines to 1,1-bis(methylthio)-2-nitroethene with cyanoacetamide and aromatic aldehydes is described. The reactions are completed within 2-5 h, in ethanol at reflux, in good to high yields (70-93%). The structures of products were deduced from their IR, mass, 1H NMR, and 13C NMR spectra. Results: Optimal reaction conditions for the synthesis of products were obtained, when ethanol was used as the solvent at reflux. This protocol involves Michael reaction, imine–enamine tautomerization, and cyclization sequences. Conclusion: This work represents an efficient synthesis of imidazo[1,2-a]pyridine, pyrido[1,2-a]pyrimidine and pyrido[1,2-a][1,3]diazepine derivatives via a one-pot, multi-component reaction. The advantages of this protocol are mild conditions, easy accessibility of reactants, absence of catalyst, high atom economy, simple work-up and purification process with no chromatographic technique.

scholarly journals [DMImd-DMP]: A highly efficient and reusable catalyst for the synthesis of 4H-benzo[b]pyran derivatives

2019 ◽  
Vol 25 (1) ◽  
pp. 167-179 ◽  
Author(s):  
Mohamed Abdenour Redouane ◽  
Naima Khiri-Meribout ◽  
Saida Benzerka ◽  
Abdelmadjid Debache
Keyword(s):  
Carbonyl Compounds ◽  
Aromatic Aldehydes ◽  
Reusable Catalyst ◽  
Atom Economy ◽  
One Pot ◽  
Dimethyl Phosphate ◽  
Pyrazolone Derivatives ◽  
Simple Product ◽  
High Yields ◽  
Active Methylene

AbstractA series of substituted 4H-pyrans derivatives were synthesized by a one-pot, multi-component reaction of aromatic aldehydes, malononitrile, and pyrazolone derivatives or active methylene carbonyl compounds such as dimedone, in the presence of 1,3-dimethyl imidazolium dimethyl phosphate [DMImd-DMP] as a catalyst in aqueous ethanol. Recyclability of the catalyst, high yields, simple product isolation and high atom economy are the noteworthy aspects of this protocol.

Catalytic asymmetric synthesis of cyclopropylphosphonates — Catalysts' scope and reactivity

2005 ◽  
Vol 83 (6-7) ◽  
pp. 533-542 ◽  
Author(s):  
André B Charette ◽  
Jean-Emmanuel Bouchard
Keyword(s):  
Transition Metal ◽  
Asymmetric Synthesis ◽  
Copper Catalysts ◽  
Ruthenium Catalysts ◽  
Catalytic Asymmetric Synthesis ◽  
Reaction Proceeds ◽  
Transition Metal Catalyzed ◽  
Diazo Reagents ◽  
Metal Catalyzed ◽  
High Yields

The transition metal-catalyzed cyclopropanation of alkenes using α-diazomethylphosphonates leads to cyclopropylphosphonate derivatives in high yields. The reaction proceeds well with copper, rhodium, and ruthenium catalysts. The best catalysts for the enantioselective version are either Evans' Cu·bis(oxazoline) or Nishiyama's Ru·pybox.Key words: cyclopropylphosphonic acids, copper catalysts, ruthenium catalysts, cyclopropanation, diazo reagents.

scholarly journals Micellar Suzuki Cross-Coupling between Thiophene and Aniline in Water and under Air

Organics ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 415-423
Author(s):  
Dawod Yousif ◽  
Silvia Tombolato ◽  
Elmehdi Ould Maina ◽  
Riccardo Po ◽  
Paolo Biagini ◽  
...  
Keyword(s):  
Room Temperature ◽  
Reaction Times ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Inert Atmosphere ◽  
Chemical Transformations ◽  
Cross Coupling Reaction ◽  
Aqueous Environments ◽  
Metal Catalyzed ◽  
High Yields

The Suzuki–Miyaura cross-coupling reaction plays a fundamental role in modern synthetic organic chemistry, both in academia and industry. For this reason, scientists continue to search for new, more effective, cheaper and environmentally friendly procedures. Recently, micellar synthetic chemistry has been demonstrated to be an excellent strategy for achieving chemical transformations in a more efficient way, thanks to the creation of nanoreactors in aqueous environments using selected surfactants. In particular, the cheap and commercially available surfactant Kolliphor EL (a polyethoxylated castor oil derivative) has been used with success to achieve metal-catalyzed transformations in water with high yields and short reaction times, with the advantage of using air-sensitive catalysts without the need for inert atmosphere. In this work, the Kolliphor EL methodology was applied to the Suzuki cross-coupling reaction between thiophene and aniline, using the highly effective catalyst Pd(dtbpf)Cl2. The cross-coupling products were achieved at up to 98% yield, with reaction times of up to only 15 min, working at room temperature and without the need for inert atmosphere.

Microwave Domino Diastereoselective Synthesis of Novel Trans-4,5-Dihydro-1H-Furo[2,3-c]Pyrazoles Using Pyridinium Salts in an Aqueous Medium

2018 ◽  
Vol 42 (4) ◽  
pp. 219-223 ◽  
Author(s):  
Afshin Yazdani-Elah-Abadi ◽  
Reza Morekian ◽  
Nasim Simin ◽  
Mojtaba Lashkari
Keyword(s):  
Hydrazine Hydrate ◽  
Pyridinium Salt ◽  
Biologically Active ◽  
Domino Reaction ◽  
Diastereoselective Synthesis ◽  
Atom Economy ◽  
One Pot ◽  
Aryl Aldehyde ◽  
High Yields ◽  
Work Up

Novel fused 4,5-dihydro-1 H-furo[2,3- c]pyrazole derivatives containing both biologically active pyrazole and furan templates are synthesised by a one-pot two-step four-component domino reaction involving hydrazine hydrate, a β-keto ester, an aromatic aldehyde and a pyridinium salt catalysed by DABCO with high diastereoselectivity in H2O under microwave irradiation. To minimise the formation of byproducts, the hydrazine hydrate and ethyl acetoacetate were first irradiated until a pyrazolone was formed. Next, the aryl aldehyde, the pyridinium salt and DABCO were added and the reaction could be completed in good to excellent yields. The salient features of this eco-friendly methodology are highlighted by its short reaction time (10–12 min), high yields, high atom-economy, efficiency of producing five new bonds (2C–C, C=N, C–N and one C–O), two new rings and two stereocentres in a single operation, absence of any tedious work-up or purification and avoidance of separation of intermediates.

scholarly journals Efficient and Facile One-Pot Synthesis of Novel Benzimidazoles using Rice Husk

2020 ◽  
pp. 27-32
Author(s):  
Suman Suman ◽  
Rajvir Singh ◽  
Susheel Gulati ◽  
Suprita Suprita
Keyword(s):  
Rice Husk ◽  
Room Temperature ◽  
Rice Husk Ash ◽  
Atom Economy ◽  
One Pot ◽  
Green Catalyst ◽  
Filter Pump ◽  
High Yields ◽  
Work Up ◽  
Layer Chromatography

New and facile one-pot approach for the synthesis of substituted benzimidazoles from the reaction of substituted benzaldehyde and o-phenylenediamine room temperature using Rice Husk Ash: CaCl2 (RHA:CaCl2) as a green catalyst was presented in the paper. After the completion of the reaction, the reaction mixture was poured into ice-coldwater with stirring, and the precipitated product was filtered using the filter pump. The crude product was then recrystallized from ethanol to give analytically pure samples in good to excellent yield. The purity of compounds were characterized by melting point and thin-layer chromatography. The synthesized compounds were characterized by using 1HNMR and FTIR spectral techniques.Metal-free, short reaction time, high yields, mild reaction condition, simple work-up, high atom economy, cost-effectiveness, and no need for column purification are some beauties of this methodology.

Recent Advances in One-Pot Enyne Metathesis Processes for the Preparation of Biologically and Medicinally Relevant Compounds

Synthesis ◽  
2020 ◽  
Author(s):  
Massimo Serra ◽  
Eric Bernardi ◽  
Lino Colombo
Keyword(s):  
Environmental Sustainability ◽  
Scientific Literature ◽  
Diels Alder ◽  
Chemical Transformations ◽  
Enyne Metathesis ◽  
One Pot ◽  
Biologically Relevant ◽  
Bond Forming ◽  
Wide Range ◽  
Metal Catalyzed

AbstractEnyne metathesis reactions are powerful tools for the preparation of a wide range of synthetic and natural chemical substances with increasing efficiency and environmental sustainability. The driving force of the reaction is the formation of a stable conjugated system, i.e., a diene, which through further functionalization steps can be used for the construction of skeletally complex molecular architectures. These concepts are exploited to design cascade reaction sequences, where multiple rings can be formed in a one-pot fashion by combining metathetic protocols with various chemical transformations. The strong correlation between synthetic organic chemistry and medicinal chemistry prompted us to review the most notable approaches for the synthesis of biologically relevant compounds via enyne metathesis-based one-pot processes. With the aim to provide a modern and practical overview, by taking into consideration the scientific literature on this topic, we have focused the majority of our attention on the research performed in the last decade. This review covers the literature from 2003 to 2020.1 Introduction2 Ethylene-Mediated Processes3 RCEYM/CM and CEYM/RCM Processes4 Enyne Metathesis/Diels–Alder-Based Processes5 RCM of Dienynes6 RCM of Tethered Dienynes7 Relay Metathesis8 Ring-Rearrangement Metathesis9 RCEYM/Transition-Metal-Catalyzed C–C Bond-Forming Processes10 Conclusions11 List of Acronyms

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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