scholarly journals Cobalt-Catalyzed Multisubstituted Allylation of Chelation-Assisted C-H bond of (Hetero)arenes with Cyclopropenes

2021 ◽  
Author(s):  
Kuppan Ramachandran ◽  
Pazhamalai Anbarasan
Keyword(s):  
Organic Synthesis ◽  
Ring Opening ◽  
Highly Strained

Cyclopropenes are highly strained three-membered carbocycle, which offers unique reactivity in organic synthesis. Herein, Cp*CoIII-catalyzed ring-opening isomerization of cyclopropenes to cobalt vinylcarbene has been utilized for the synthesis of multisubstituted...

Synthesis and Applications of Cyclopropanones and their Equivalents as Three-Carbon Building Blocks in Organic Synthesis

Synthesis ◽  
2021 ◽  
Author(s):  
Yujin Jang ◽  
Roger Machin-Rivera ◽  
Vincent Lindsay
Keyword(s):  
Organic Synthesis ◽  
Ring Opening ◽  
Building Blocks ◽  
Ring Expansion ◽  
Ring System ◽  
Small Ring ◽  
Future Directions ◽  
Highly Strained ◽  
And Storage

Cyclopropanone derivatives constitute highly strained cycloalkanones with promising applications as three-carbon building blocks in organic synthesis. Due to the presence of a ketone in such a small ring system, all C–C bonds and the carbonyl group are considered to be labile in suitable conditions, leading to a wide variety of synthetic disconnections, including nucleophilic addition, ring expansion, ring-opening and (formal) cycloaddition. Despite their synthetic potential, the widespread adoption of cyclopropanones as substrates has been considerably hampered by the difficulties associated with the preparation and storage of such unstable compounds, prompting the development of cyclopropanone surrogates that can equilibrate to parent ketone in situ via elimination. This review summarizes the syntheses and applications of cyclopropanone derivatives and their equivalents, and offers a perspective of the state of the field as well as its expected future directions.

scholarly journals Alkyl substituted [2.2]paracyclophane-1,9-dienes

2016 ◽  
Vol 14 (25) ◽  
pp. 6079-6087 ◽  
Author(s):  
Benjamin J. Lidster ◽  
Dharam R. Kumar ◽  
Andrew M. Spring ◽  
Chin-Yang Yu ◽  
Madeleine Helliwell ◽  
...  
Keyword(s):  
Ring Opening ◽  
Ring Opening Metathesis Polymerization ◽  
Metathesis Polymerization ◽  
Highly Strained

Highly strained alkyl-substituted [2.2]paracyclophane-1,9-dienes, suitable for ring opening metathesis polymerization to poly(phenylene vinylenes), have been prepared in excellent yields.

scholarly journals Dewar Heterocycles as Versatile Monomers for Ring-Opening Metathesis Polymerization

2020 ◽  
Author(s):  
Sepand Nistanaki ◽  
Hosea Nelson
Keyword(s):  
Ring Opening ◽  
Water Soluble ◽  
Ring Opening Metathesis Polymerization ◽  
Valence Isomerization ◽  
Metathesis Polymerization ◽  
Grubbs Catalysts ◽  
Amino Acid Polymers ◽  
Highly Strained ◽  
Acetylene Derivatives ◽  
Soluble Poly

We report the utility of readily available heterocycles as precursors to unique ring-opening metathesis polymerization (ROMP) monomers. Photochemical valence isomerization reactions of pyridones, dihydropyridines, and pyrones dearomatize the parent heterocycles to their highly strained Dewar isomers, which readily engage in controlled ROMP reactions using Grubbs catalysts. This strategy is used to access novel polymer backbones that contain strained β-lactam and azetidine cores, which can be further derivatized using post-polymerization chemistries. We demonstrate this through the synthesis of water-soluble β-amino acid polymers and soluble poly(acetylene) derivatives.

scholarly journals Cobalt Catalysis Enables Regioselective Ring-opening of Epoxides with Aryl Halides

2021 ◽  
Author(s):  
Aleksandra Potrząsaj ◽  
Mateusz Musiejuk ◽  
Wojciech Chaładaj ◽  
Maciej Giedyk ◽  
Dorota Gryko
Keyword(s):  
Vitamin B12 ◽  
Organic Synthesis ◽  
Blue Light ◽  
Catalytic System ◽  
Ring Opening ◽  
Aryl Halides ◽  
Light Irradiation ◽  
Selective Synthesis ◽  
Ring Opening Of Epoxides

Ring-opening of epoxides furnishing either linear or branched products belongs to the group of classic transformations in organic synthesis. However, the regioselective cross-electrophile coupling of aryl epoxides with aryl halides still represents a key challenge. Herein, we report vitamin B12/Ni dual-catalytic system that allows for the selective synthesis of linear products under blue-light irradiation.

DABCO as a Base and an Organocatalyst in Organic Synthesis: A Review

2020 ◽  
Vol 7 (2) ◽  
pp. 146-162
Author(s):  
Dinesh K. Jangid
Keyword(s):  
Organic Synthesis ◽  
Ring Opening ◽  
High Selectivity ◽  
Solid Catalyst ◽  
Cycloaddition Reactions ◽  
Coupling Reactions ◽  
Henry Reaction ◽  
Environmental Friendly ◽  
Ring Opening Reactions ◽  
Catalytic Applications

One of the organocatalysts 1,4-diazabicyclo[2.2.2]octane (DABCO) is an excellent solid catalyst in a number of reactions. It is also a good nucleophile and a base in numerous reactions for the synthesis of heterocycles. DABCO catalyzes many reactions like cycloaddition reactions, coupling reactions, Baylis-Hillman reaction, Henry reaction, ring opening reactions, etc. One more advanced feature of these reactions is that they proceed through environmental friendly pathway. DABCO has more advantages than other organic catalysts because it is an inexpensive, non.toxic base, an ecofriendly and a highly reactive catalyst for building of organic frameworks, which produce the desired products in excellent yields with high selectivity. Many catalytic applications of DABCO have been reported for the synthesis of an organic framework which has been discussed in this review.

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