scholarly journals Morpholin-2-one Derivatives via Intramolecular Acid-Catalyzed Hydroamination

Synthesis ◽  
2019 ◽  
Vol 51 (07) ◽  
pp. 1643-1648 ◽  
Author(s):  
David Knight ◽  
Thomas Wirth ◽  
Abdul Hadi Aldmairi
Keyword(s):  
Amino Acids ◽  
Catalytic Amount ◽  
Practical Method ◽  
Trifluoromethanesulfonic Acid ◽  
Reaction Conditions ◽  
Available N ◽  
Metal Free ◽  
Acid Catalyzed

Substituted morpholin-2-one derivatives were readily obtained in two steps starting from commercially available N-protected amino acids. In a metal-free and practical method, a catalytic amount of trifluoromethanesulfonic acid was sufficient to generate morpholinones under mild reaction conditions in an intramolecular hydroamination reaction in good to excellent yields.

DABCO Promoted Regioselective Synthesis of New Diversely Functionalized 3-Hydroxy-2-Oxindole Scaffolds

2014 ◽  
Vol 67 (5) ◽  
pp. 768 ◽  
Author(s):  
Pramod B. Thakur ◽  
Jagdeesh B. Nanubolu ◽  
Harshadas M. Meshram
Keyword(s):  
Catalytic Amount ◽  
Regioselective Synthesis ◽  
Reaction Conditions ◽  
Metal Free ◽  
Structural Framework

An efficient and highly regioselective γ-addition of β-keto sulfones on isatins has been achieved in the presence of a catalytic amount of 1,4-diazabicyclo[2.2.2]octane (DABCO) to afford a γ-(3-hydroxy-2-oxindole)-β-keto sulfone structural framework. The scope of the method is tested by screening a series of isatin electrophiles as well as β-keto sulfones. The described method was found to be very handy and provides straightforward access for the diversely functionalized 3-β-keto sulfone substituted-3-hydroxy-2-oxindole structural scaffolds in very good yields from readily available starting materials under metal-free reaction conditions.

scholarly journals Chiral Tetrahydropyridines via FeCl3-Catalyzed Carbonyl-Olefin Metathesis

2019 ◽  
Author(s):  
Katie Rykaczewski ◽  
Emilia J. Groso ◽  
Hannah L. Vonesh ◽  
Mario Gaviria ◽  
Alistair D. Richardson ◽  
...  
Keyword(s):  
Amino Acids ◽  
Lewis Acid ◽  
Olefin Metathesis ◽  
Unnatural Amino Acids ◽  
Environmentally Benign ◽  
Reaction Conditions ◽  
Reaction Proceeds ◽  
Acid Catalyzed

<div> <div> <p>Herein, we describe the application of Lewis acid-catalyzed carbonyl-olefin metathesis towards the synthesis of chiral, substituted tetrahydropyridines from commercially available amino acids as chiral pool reagents. This strategy relies on FeCl<sub>3</sub> as an inexpensive and environmentally benign catalyst and enables access to a variety of substituted tetrahydropyridines under mild reaction conditions. The reaction proceeds with complete stereoretention and is viable for a variety of natural and unnatural amino acids to provide the corresponding tetrahydropyridines in up to 99% yield.</p> </div> </div> <br>

A Mild and Practical Method for Deprotection of Aryl Methyl/ Benzyl/Allyl Ethers with HPPh2 and tBuOK

2021 ◽  
Author(s):  
WenJing Pan ◽  
Chenchen Li ◽  
Haoyin Zhu ◽  
Fangfang Li ◽  
Tao Li ◽  
...  
Keyword(s):  
Practical Method ◽  
Reaction Conditions ◽  
Metal Free ◽  
Allyl Ethers ◽  
Aryl Ethers ◽  
Aryl Methyl ◽  
General Method

A general method for the demethylation, debenzylation, and deallylation of aryl ethers using HPPh2 and tBuOK is reported. The reaction features mild and metal-free reaction conditions, broad substrate scope, good...

A General Method for the Synthesis of 11H-indeno[1,2-b]quinoxalin-11-ones and 6H-indeno[1,2-b]pyrido[3,2-e]pyrazin-6-one Derivatives using Mandelic Acid as an Efficient Organo-catalyst at Room Temperature

2021 ◽  
Vol 08 ◽  
Author(s):  
Aditi Sharma ◽  
Gurpreet Kaur ◽  
Diksha Singh ◽  
Vivek Kumar Gupta ◽  
Bubun Banerjee
Keyword(s):  
Mandelic Acid ◽  
Room Temperature ◽  
Aqueous Ethanol ◽  
Low Cost ◽  
Catalytic Amount ◽  
Reaction Conditions ◽  
Metal Free ◽  
Naturally Occurring ◽  
Column Chromatographic ◽  
General Method

Aims: Synthesis of 11H-indeno[1,2-b]quinoxalin-11-ones as well as 6H-indeno[1,2-b]pyrido[3,2-e]pyrazin-6-one derivatives under greener conditions. Background: Quinoxaline and related skeletons are very common in naturally occurring bioactive compounds. Objective: Design a facile, green and organo-catalyzed method for the synthesis of 11H-indeno[1,2-b]quinoxalin-11-ones as well as 6H-indeno[1,2-b]pyrido[3,2-e]pyrazin-6-one derivatives. Methods: Both the scaffolds were synthesized via the condensation of ninhydrin and o-phenylenediamines or pyridine-2,3-diamines respectively by using a catalytic amount of mandelic acid as an efficient, commercially available, low cost, organo-catalyst in aqueous ethanol at room temperature. Results: Mild reaction conditions, use of metal-free organocatalyst, non-toxic solvent, ambient temperature, and no column chromatographic separation are some of the notable advantages of our developed protocol. Conclusion: In conclusion, we have developed a simple, mild, facile and efficient method for the synthesis of structurally diverse 11H-indeno[1,2-b]quinoxalin-11-one derivatives via the condensation reactions of ninhydrin and various substituted benzene-1,2-diamines using a catalytic amount of mandelic acid as a commercially available metal-free organo-catalyst in aqueous ethanol at room temperature. Under the same optimized reaction conditions, synthesis of 6H-indeno[1,2-b]pyrido[3,2-e]pyrazin-6-one derivatives was also accomplished with excellent yields by using pyridine-2,3-diamines instead of o-phenylenediamine.

scholarly journals Chiral Tetrahydropyridines via FeCl3-Catalyzed Carbonyl-Olefin Metathesis

2019 ◽  
Author(s):  
Katie Rykaczewski ◽  
Emilia J. Groso ◽  
Hannah L. Vonesh ◽  
Mario Gaviria ◽  
Alistair D. Richardson ◽  
...  
Keyword(s):  
Amino Acids ◽  
Lewis Acid ◽  
Olefin Metathesis ◽  
Unnatural Amino Acids ◽  
Environmentally Benign ◽  
Reaction Conditions ◽  
Reaction Proceeds ◽  
Acid Catalyzed

<div> <div> <p>Herein, we describe the application of Lewis acid-catalyzed carbonyl-olefin metathesis towards the synthesis of chiral, substituted tetrahydropyridines from commercially available amino acids as chiral pool reagents. This strategy relies on FeCl<sub>3</sub> as an inexpensive and environmentally benign catalyst and enables access to a variety of substituted tetrahydropyridines under mild reaction conditions. The reaction proceeds with complete stereoretention and is viable for a variety of natural and unnatural amino acids to provide the corresponding tetrahydropyridines in up to 99% yield.</p> </div> </div> <br>

Methanesulfonic Acid Catalyzed Friedel–Crafts Reaction of Electron-Rich Arenes with N-Arylmaleimides: A Highly Efficient Metal-Free Route To Access 3-Arylsuccinimides

Synthesis ◽  
2021 ◽  
Author(s):  
Rama Krishna Peddinti ◽  
Deepti Gairola
Keyword(s):  
Methanesulfonic Acid ◽  
Environmentally Benign ◽  
Direct Connection ◽  
Reaction Conditions ◽  
Metal Free ◽  
Bond Forming ◽  
Highly Efficient ◽  
Acid Catalyzed

AbstractFriedel–Crafts reaction is widely used for the C–C bond forming reaction to enable the direct connection of electron-rich arenes to electron-deficient olefins with high regioselectivity. Herein, a highly efficient, metal-free, and environmentally benign F–C strategy of electron-rich arenes with N-arylmaleimides has been developed for the construction of 3-arylsuccinimides in the presence of a green reagent methanesulfonic acid under mild reaction conditions. This highly facile and high-yielding protocol has compatibility with different electron-rich arenes.

scholarly journals Helicene synthesis by Brønsted acid-catalyzed cycloaromatization in HFIP [(CF3)2CHOH]

2021 ◽  
Vol 17 ◽  
pp. 396-403
Author(s):  
Takeshi Fujita ◽  
Noriaki Shoji ◽  
Nao Yoshikawa ◽  
Junji Ichikawa
Keyword(s):  
Bond Formation ◽  
Catalytic Amount ◽  
Trifluoromethanesulfonic Acid ◽  
Higher Order ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Facile Synthesis ◽  
Brönsted Acid ◽  
Acid Catalyzed

A facile synthesis of carbo- and heterohelicenes was achieved via tandem cycloaromatization of bisacetal precursors, which were readily prepared through C–C bond formation by Suzuki–Miyaura coupling. This cyclization was efficiently realized by a catalytic amount of trifluoromethanesulfonic acid (TfOH) in a cation-stabilizing solvent, 1,1,1,3,3,3-hexafluoropropan-2-ol (HFIP), which readily allowed gram-scale syntheses of higher-order helicenes, double helical helicenes, and heterohelicenes.

Naturally Occurring Organic Acid-catalyzed Facile Diastereoselective Synthesis of Biologically Active (E)-3-(arylimino)indolin-2-one Derivatives in Water at Room Temperature

2019 ◽  
Vol 23 (16) ◽  
pp. 1778-1788 ◽  
Author(s):  
Gurpreet Kaur ◽  
Arvind Singh ◽  
Kiran Bala ◽  
Mamta Devi ◽  
Anjana Kumari ◽  
...  
Keyword(s):  
Room Temperature ◽  
Biologically Active ◽  
Environmentally Benign ◽  
Diastereoselective Synthesis ◽  
Substituted Anilines ◽  
Reaction Conditions ◽  
Naturally Occurring ◽  
Acid Catalyzed ◽  
Reaction Media ◽  
Column Chromatographic

A simple, straightforward and efficient method has been developed for the synthesis of (E)-3-(arylimino)indolin-2-one derivatives and (E)-2-((4-methoxyphenyl)imino)- acenaphthylen-1(2H)-one. The synthesis of these biologically-significant scaffolds was achieved from the reactions of various substituted anilines and isatins or acenaphthaquinone, respectively, using commercially available, environmentally benign and naturally occurring organic acids such as mandelic acid or itaconic acid as catalyst in aqueous medium at room temperature. Mild reaction conditions, energy efficiency, good to excellent yields, environmentally benign conditions, easy isolation of products, no need of column chromatographic separation and the reusability of reaction media are some of the significant features of the present protocol.

p-Sulfonic acid calix[n]arene catalyzed synthesis of bioactive heterocycles: A review

2020 ◽  
Vol 24 ◽  
Author(s):  
Bubun Banerjee ◽  
Gurpreet Kaur ◽  
Navdeep Kaur
Keyword(s):  
Supramolecular Chemistry ◽  
Sulfonic Acid ◽  
Catalytic Efficiency ◽  
The Other ◽  
Reaction Conditions ◽  
Metal Free ◽  
Bioactive Scaffolds ◽  
Wide Range ◽  
Efficient Alternative ◽  
Bioactive Heterocycles

: Metal-free organocatalysts are becoming an important tool for the sustainable developments of various bioactive heterocycles. On the other hand, during last two decades, calix[n]arenes have been gaining considerable attention due to their wide range of applicability in the field of supramolecular chemistry. Recently, sulfonic acid functionalized calix[n] arenes are being employed as an efficient alternative catalyst for the synthesis of various bioactive scaffolds. In this review we have summarized the catalytic efficiency of p-sulfonic acid calix[n]arenes for the synthesis of diverse biologically promising scaffolds under various reaction conditions. There is no such review available in the literature showing the catalytic applicability of p-sulfonic acid calix[n]arenes. Therefore, we strongly believe that this review will surely attract those researchers who are interested about this fascinating organocatalyst.

Synthesis of Pyrrolo[1,2-a][1,6]- and [1,8]naphthyridines by Alkyne-Carbonyl Metathesis

Synthesis ◽  
2020 ◽  
Author(s):  
Peter Ehlers ◽  
Peter Langer ◽  
Marian Blanco Ponce ◽  
Silvio Parpart ◽  
Alexander Villinger ◽  
...  
Keyword(s):  
Heterocyclic Compounds ◽  
Metathesis Reaction ◽  
Synthetic Methodology ◽  
Facile Synthesis ◽  
Reaction Conditions ◽  
One Pot ◽  
Metal Free ◽  
Modular Synthesis

AbstractA concise and modular synthesis of pyrrolo[1,2-a][1,6]- and [1,8]naphthyridines by a one-pot two-step reaction consisting of electrophilic acylation followed by an alkyne-carbonyl-metathesis reaction as the final cyclization step is reported. This developed synthetic methodology allows the facile synthesis of these heterocyclic core structures in mainly high overall yields under metal-free conditions. Reaction conditions are carefully optimized and display a novel supplement to access these tricyclic heterocyclic compounds.

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