ChemInform Abstract: 2-Aryl-3,4-dihydropyrans as Building Blocks for Organic Synthesis: Ring-Opening Reactions with Nucleophiles.

ChemInform ◽  
2012 ◽  
Vol 43 (6) ◽  
pp. no-no
Author(s):  
Minghao Li ◽  
Yanlong Gu
Keyword(s):  
Organic Synthesis ◽  
Ring Opening ◽  
Building Blocks ◽  
Ring Opening Reactions ◽  
Reactions With Nucleophiles

Electrophilic Ring Opening of Small Heterocycles

Synthesis ◽  
2017 ◽  
Vol 49 (24) ◽  
pp. 5307-5319 ◽  
Author(s):  
Chuan Wang
Keyword(s):  
Ethylene Oxide ◽  
Functional Groups ◽  
Organic Synthesis ◽  
Ring Opening ◽  
Building Blocks ◽  
Nickel Titanium ◽  
Ring Opening Reactions ◽  
Palladium Catalyzed ◽  
Ring Opening Of Epoxides ◽  
Nucleophilic Ring Opening

Small heterocycles, such as epoxides, aziridines, and ox­etanes are among the most useful building blocks in organic synthesis. Through electrophilic ring opening of these molecules, various electrophilic functional groups can be installed, which cannot be achieved via classic nucleophilic ring-opening reactions. In this review, the developments of electrophilic ring opening of small heterocycles are surveyed and organized according to the types of metal promoters.1 Introduction2 Electrophilic Ring Opening of Small Heterocycles Using Stoichiometric Metals2.1 Lithium-Mediated Electrophilic Ring Opening of Epoxides and Oxetanes2.2 Chromium-Mediated Electrophilic Ring Opening of Vinyl Epoxides2.3 Tin-Mediated Electrophilic Ring Opening of Vinyl Epoxides2.4 Samarium-Mediated Electrophilic Ring Opening of Vinyl and Alkynyl Epoxides2.5 Titanium-Mediated Electrophilic Ring Opening of Epoxides2.6 Platinum, Palladium, and Nickel-Mediated Electrophilic Ring Opening of 1,1-Dimethyl Ethylene Oxide3 Catalytic Electrophilic Ring Opening of Small Heterocycles3.1 Titanium-Catalyzed Electrophilic Ring Opening of Epoxides3.2 Palladium-Catalyzed Electrophilic Ring Opening of Vinyl and Alkynyl Small Heterocycles3.3 Iron-Catalyzed Electrophilic Ring Opening of Oxetanes3.4 Scandium-Catalyzed Electrophilic Ring Opening of Vinyl Epoxides3.5 Iridium-Catalyzed Electrophilic Ring Opening of 2-Methyl 2-Vinyl­oxiranes3.6 Nickel-Catalyzed Electrophilic Ring Opening of Epoxides and Aziridines3.7 Nickel–Titanium-Cocatalyzed Electrophilic Ring Opening of Epoxides4 Summary

scholarly journals Ring Opening of Donor–Acceptor Cyclopropanes with N-Nucleo­philes

Synthesis ◽  
2017 ◽  
Vol 49 (14) ◽  
pp. 3035-3068 ◽  
Author(s):  
Ekaterina Budynina ◽  
Konstantin Ivanov ◽  
Ivan Sorokin ◽  
Mikhail Melnikov
Keyword(s):  
Ring Opening ◽  
Building Blocks ◽  
Simple Approach ◽  
Secondary Amines ◽  
Primary Amines ◽  
Pyrrole Derivatives ◽  
Heteroaromatic Compounds ◽  
Azide Ion ◽  
Ring Opening Reactions ◽  
Donor Acceptor

Ring opening of donor–acceptor cyclopropanes with various N-nucleophiles provides a simple approach to 1,3-functionalized compounds that are useful building blocks in organic synthesis, especially in assembling various N-heterocycles, including natural products. In this review, ring-opening reactions of donor–acceptor cyclopropanes with amines, amides, hydrazines, N-heterocycles, nitriles, and the azide ion are summarized.1 Introduction2 Ring Opening with Amines3 Ring Opening with Amines Accompanied by Secondary Processes Involving the N-Center3.1 Reactions of Cyclopropane-1,1-diesters with Primary and Secondary Amines3.1.1 Synthesis of γ-Lactams3.1.2 Synthesis of Pyrroloisoxazolidines and -pyrazolidines3.1.3 Synthesis of Piperidines3.1.4 Synthesis of Azetidine and Quinoline Derivatives3.2 Reactions of Ketocyclopropanes with Primary Amines: Synthesis of Pyrrole Derivatives3.3 Reactions of Сyclopropane-1,1-dicarbonitriles with Primary Amines: Synthesis of Pyrrole Derivatives4 Ring Opening with Tertiary Aliphatic Amines5 Ring Opening with Amides6 Ring Opening with Hydrazines7 Ring Opening with N-Heteroaromatic Compounds7.1 Ring Opening with Pyridines7.2 Ring Opening with Indoles7.3 Ring Opening with Di- and Triazoles7.4 Ring Opening with Pyrimidines8 Ring Opening with Nitriles (Ritter Reaction)9 Ring Opening with the Azide Ion10 Summary

scholarly journals SnCl4-catalyzed Solvent-free Acetolysis of 2,7-Anhydrosialic Acid Derivatives

2019 ◽  
Author(s):  
Kesatebrhan Haile Asressu ◽  
Cheng-Chung Wang
Keyword(s):  
Sialic Acid ◽  
Lewis Acids ◽  
Ring Opening ◽  
Building Blocks ◽  
Solvent Free ◽  
Biologically Active ◽  
Protecting Group ◽  
Free Ring ◽  
Ring Opening Reactions ◽  
Acid Catalyzed

Sialic acid-containing glycans are found in different sialic acid forms and a variety of glycosidic linkages in biologically active glycoconjugates. Hence, the preparation of suitably protected sialyl building blocks requires high attention in order to access glycans in pure form. In this line, various C-5 substituted 2,7-anhydrosialic acid derivatives bearing both electron donating and withdrawing protecting groups were synthesized and subjected to different Lewis acid-catalyzed solvent free ring opening reactions at room temperature in the presence of acetic anhydride. Among the various Lewis acids tested, the desired acetolysized products were obtained in moderate yields under a tin(IV) chloride catalysis system. Our methodology can be extended to regioselective protecting group installation and manipulation towards a number of thiosialoside and halide donors.

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.

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.

Sign in / Sign up

Export Citation Format

Share Document