scholarly journals Cross metathesis of unsaturated epoxides for the synthesis of polyfunctional building blocks

2015 ◽  
Vol 11 ◽  
pp. 1876-1880 ◽  
Author(s):  
Meriem K Abderrezak ◽  
Kristýna Šichová ◽  
Nancy Dominguez-Boblett ◽  
Antoine Dupé ◽  
Zahia Kabouche ◽  
...  
Keyword(s):  
Methyl Acrylate ◽  
Ring Opening ◽  
Building Blocks ◽  
Epoxide Ring ◽  
Cross Metathesis ◽  
Saturated Compound ◽  
Polyfunctional Compounds ◽  
The Cross ◽  
High Yields ◽  
Nucleophilic Ring Opening

The cross metathesis of 1,2-epoxy-5-hexene (1) with methyl acrylate and acrylonitrile was investigated as an entry to the synthesis of polyfunctional compounds. The resulting cross metathesis products were hydrogenated in a tandem fashion employing the residual ruthenium from the metathesis step as the hydrogenation catalyst. Interestingly, the epoxide ring remained unreactive toward this hydrogenation method. The saturated compound resulting from the cross metathesis of 1 with methyl acrylate was transformed by means of nucleophilic ring-opening of the epoxide to furnish a diol, an alkoxy alcohol and an amino alcohol in high yields.

Ruthenium- and Rhodium-Catalyzed Ring-Opening Coupling Reactions of Cyclopropenones with Alkenes or Alkynes

Synlett ◽  
2018 ◽  
Vol 29 (06) ◽  
pp. 717-722 ◽  
Author(s):  
Teruyuki Kondo ◽  
Ryosuke Taniguchi ◽  
Yu Kimura
Keyword(s):  
Carbon Monoxide ◽  
Catalytic Activity ◽  
Methyl Acrylate ◽  
Ring Opening ◽  
Argon Atmosphere ◽  
High Catalytic Activity ◽  
Rhodium Complexes ◽  
Coupling Reactions ◽  
Internal Alkynes ◽  
High Yields

Ru3(CO)12-catalyzed divergent ring-opening coupling reactions of a cyclopropenone with methyl acrylate (an electron-deficient alkene) are developed. Under an argon atmosphere, a decarbonylative linear codimer is obtained, while cyclopentenones are obtained under carbon monoxide (20 atm) without decarbonylation. While ruthenium complexes show no catalytic activity for the ring-opening cocyclization of cyclopropenones with ethylene (20 atm) or bicyclo[2.2.1]hept-2-ene (2-norbornene), rhodium complexes, especially [RhCl(η4-1,5-cod)]2, show high catalytic activity for the desired cocyclization reactions to give the corresponding cyclopentenones in high yields and selectivities. In addition, [RhCl(η4-1,5-cod)]2 realizes the catalytic ring-opening co­cyclization of cyclopropenones with internal alkynes to give the corresponding cyclopentadienones. In all these reactions, ruthena- or rhodacyclobutenones are considered to be key intermediates, generated by strain-driven oxidative addition of a cyclopropenone C–C bond to an ­active ruthenium or rhodium species.

Synthetically Important Ring-Opening Acylations of Alkoxybenzenes

Synthesis ◽  
2020 ◽  
Vol 52 (24) ◽  
pp. 3764-3780
Author(s):  
Ranadeep Talukdar
Keyword(s):  
Lewis Acid ◽  
Ring Opening ◽  
Building Blocks ◽  
Nucleophilic Attack ◽  
Cyclic Ketones ◽  
Wide Range ◽  
Cyclic Molecules ◽  
Nucleophilic Ring Opening ◽  
Molecular Rings

AbstractCyclic ketones, anhydrides, lactams and lactones are a particular class of molecules that are often used in synthesis, wherein their electrophilic properties are leveraged to enable facile Friedel–Crafts ring openings through nucleophilic attack at the carbonyl sp2 centre. The use of electron-rich alkoxybenzenes as nucleophiles has also become important since the discovery of the Friedel–Crafts reaction. As a result, various isomeric alkoxybenzenes are used for preparing starting materials in target-oriented syntheses. This review covers the instances of different alkoxybenzenes that are used as nucleophiles in ring-opening acylations with carbonyl-containing cyclic electrophiles, for the construction of important building blocks for multistep transformations. This review summarizes the ring-opening functionalization of three- to seven-membered molecular rings with alkoxybenzenes in a Friedel–Crafts fashion. Sometimes the rings need subtle or considerable activation by the help of Lewis acid(s), followed by nucleophilic attack. This review is aimed to be a summary of the important acylations of electron-rich alkoxybenzenes by nucleophilic ring-opening of cyclic molecules. The works cited employ a wide range of conditions and differently substituted substrates for target-oriented syntheses.1 Introduction and Scope2 Arenes for Acylative Ring Opening2.1 Three-Membered Rings: Ring Opening of Oxirane-2,3-dione2.2 Four-Membered Rings2.2.1 Ring Opening of Cyclobutanones2.2.2 Ring Opening of β-Lactams2.2.3 Ring Opening of β-Lactone2.3 Five-Membered Rings2.3.1 Ring Opening of Phthalimides2.3.2 Ring Opening of γ-Lactones2.3.3 Ring Opening of Anhydrides2.4 Six-Membered Rings2.5 Seven-Membered Rings3 Conclusion

Enantioselective formation and ring-opening of epoxides catalysed by halohydrin dehalogenases

2006 ◽  
Vol 34 (2) ◽  
pp. 291-295 ◽  
Author(s):  
D.B. Janssen ◽  
M. Majerić-Elenkov ◽  
G. Hasnaoui ◽  
B. Hauer ◽  
J.H. Lutje Spelberg
Keyword(s):  
Ring Opening ◽  
Building Blocks ◽  
Epoxide Ring ◽  
Structural Studies ◽  
Halide Ions ◽  
Catalytic Promiscuity ◽  
Agrobacterium Radiobacter ◽  
Enzymatic Production ◽  
Ring Opening Reactions ◽  
Ring Opening Of Epoxides

Halohydrin dehalogenases catalyse the conversion of vicinal halohydrins into their corresponding epoxides, while releasing halide ions. They can be found in several bacteria that use halogenated alcohols or compounds that are degraded via halohydrins as a carbon source for growth. Biochemical and structural studies have shown that halohydrin dehalogenases are evolutionarily and mechanistically related to enzymes of the SDR (short-chain dehydrogenase/reductase) superfamily. In the reverse reaction, which is epoxide-ring opening, different nucleophiles can be accepted, including azide, nitrite and cyanide. This remarkable catalytic promiscuity allows the enzymatic production of a broad range of β-substituted alcohols from epoxides. In these oxirane-ring-opening reactions, the halohydrin dehalogenase from Agrobacterium radiobacter displays high enantioselectivity, making it possible to use the enzyme for the preparation of enantiopure building blocks for fine chemicals.

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

Synthesis of Functionalized 1,4-Dioxanes with an Additional (Hetero)Aliphatic Ring

Synthesis ◽  
2018 ◽  
Vol 50 (18) ◽  
pp. 3696-3707 ◽  
Author(s):  
Oleksandr Grygorenko ◽  
Andriy Bondarenko ◽  
Andrey Tolmachev ◽  
Bohdan Vashchenko
Keyword(s):  
Ethylene Glycol ◽  
Ring Opening ◽  
Medicinal Chemistry ◽  
Building Blocks ◽  
Epoxide Ring ◽  
Reaction Sequence ◽  
Epoxide Ring Opening ◽  
Monosodium Salt ◽  
Aldehydes And Ketones ◽  
Spirocyclic Compounds

An approach to the preparation of 2-mono-, 2,2- and 2,3-disubstituted 1,4-dioxane derivatives is described. The reaction sequence commences from readily available epoxides, in most cases prepared via the Corey–Chaikovsky reaction of the corresponding aldehydes and ketones. The key step of the method is epoxide ring opening with ethylene glycol monosodium salt, followed by further cyclization of the diols obtained. The utility of the approach was demonstrated by multigram preparation of novel functionalized 1,4-dioxanes bearing additional cycloalkane, piperidine or pyrrolidine rings, mostly spirocyclic compounds, which are advanced building blocks for medicinal chemistry.

scholarly journals REACTION OF 2-HETARYL-2-(DIHYDROFURAN-2(3H)-ILIDEN)ACETONITRILES WITH AROMATIC AMINES

2020 ◽  
pp. 47-51
Author(s):  
R. Shemehen ◽  
O. Khilya ◽  
Yu. Volovenko
Keyword(s):  
Aromatic Amines ◽  
Ring Opening ◽  
Catalytic Amount ◽  
Building Blocks ◽  
Heterocyclic Ring ◽  
Ring Closure ◽  
Reaction Conditions ◽  
Ring Opening Reaction ◽  
Ring Transformations ◽  
High Yields

This article reports on the reaction of 2-hetaryl-2-(furanyl-2-ylidene)acetonitriles with aromatic amines as N-nucleophiles. 2-Hetaryl-2-(furanyl-2-ylidene)acetonitriles represent versatile building blocks in syntheses of ω-(N-aryl)alkyl substituted heterocycles due to the presence of 1,3-bielectrophilic acrylonitrile fragment functionalized with unsaturated heterocyclic ring and nucleophilic azaheterocyclic moiety. The carbonyl group masked within the N-arylpyrrolidinylidene fragment which undergoes a ring opening through the reaction with nucleophiles. So, a method for the synthesis of 2-hetaryl-6-hydroxy-3-(arylamino)hex-2-enenitriles and 2-hetaryl-2-(N-arylpyrrolidin-2-ylidene)acetonitriles has been developed by us. The proposed scheme is based on the available reagents using. As a result of Michael addition, the aromatic amines to 2-hetaryl-2-(furanyl-2-ylidene)acetonitriles followed by ring transformations has formed two types of products, depending on the reaction conditions. The reaction of substituted furanylylideneacetonitriles with aromatic amines proceeds in good to high yields affording the corresponding 3-(arylamino)hex-2-enenitriles and 2-(N-arylpyrrolidin-2-ylidene)acetonitriles derivatives. The stereochemistry of the ring-opening reaction follows the rules of a classical SN2 mechanism. The resulting linear products can be cyclized to 2-hetaryl-2-(furanyl-2-ylidene)acetonitriles in high yields by treatment with the catalytic amount of acid or the equimolar amount of aromatic amines. Under these conditions 2-hetaryl-6-hydroxy-3-(arylamino)hex-2-enenitriles arising from reaction gives the ring closure. Since both ring-opening and cyclisation occur with fixed stereochemistry the reaction appears a valuable modification to the preparation of acetonitriles derivatives.

Regioselective palladium-catalyzed ring-opening reactions of C1-substituted oxabenzonorbornadienes

2014 ◽  
Vol 92 (9) ◽  
pp. 888-895 ◽  
Author(s):  
Mohammed Abdul Raheem ◽  
Michael Edmunds ◽  
William Tam
Keyword(s):  
Ring Opening ◽  
Aryl Group ◽  
Aryl Iodide ◽  
Electronic Nature ◽  
Ring Opening Reactions ◽  
Palladium Catalyzed ◽  
High Yields ◽  
Nucleophilic Ring Opening

The effect of ethyl and methoxycarbonyl substitution on the C1 position of oxabenzonorbornadienes undergoing palladium-catalyzed nucleophilic ring opening was investigated with a variety of aryl iodide nucleophiles. Electron-withdrawing groups in the C1 position or on the aryl iodide afforded lower yields and led to aromatization of products. The presence of an electron-donating group in either position provided high yields in all cases. Despite variances in electronic nature, all trials produced a single regioisomeric product resulting from addition of the aryl group to the olefin carbon farthest from the C1 substituent. Based on these findings, a mechanism has also been proposed.

Adventures and Detours in the Synthesis of Hydropentalenes

Synlett ◽  
2020 ◽  
Author(s):  
Sabine Laschat ◽  
Max Deimling ◽  
Anna Zens ◽  
Natja Park ◽  
Christine Hess ◽  
...  
Keyword(s):  
Crown Ether ◽  
Asymmetric Catalysis ◽  
Ring Opening ◽  
Building Blocks ◽  
Biological Properties ◽  
Oxidative Cyclization ◽  
Ring Closing Metathesis ◽  
Ene Reactions ◽  
Cross Metathesis ◽  
Synthetic Approaches

Functionalized hydropentalenes (i.e., bicyclo[3.3.0]octanones) constitute important building blocks for natural products and for ligands for asymmetric catalysis. The assembly and tailored functionalization of this convex roof-shaped scaffold is challenging and has motivated a variety of synthetic approaches including our own contributions, which will be presented in this account.1 Introduction2 Biosynthesis of Hydropentalenes3 Hydropentalenes through the Pauson–Khand Reaction4 Hydropentalenes through Transannular Oxidative Cyclization of Cycloocta-1,4-diene5 Functionalization of Bicyclo[3.3.0]octan-1,4-dione to Dodecahydrocyclopenta[a]indenes6 Functionalization of Bicyclo[3.3.0]octan-1,4-diones to Crown Ether Hybrids7 Functionalization of Bicyclo[3.3.0]octan-1,4-dione to Cylindramide8 Tandem Ring-Opening Metathesis/Ring-Closing Metathesis/Cross-Metathesis of Bicyclo[2.2.1]heptanes9 Functionalization of Bicyclo[3.3.0]octan-1,4-dione to Geodin A10 Hydropentalenes through Enantioselective Desymmetrization of Weiss Diketones11 Functionalization of Weiss Diketones by Carbonyl Ene Reactions12 Functionalization of the Weiss Diketone to Cylindramide and Geodin A Core Units13 Biological Properties of Bicyclo[3.3.0]octanes14 Hydropentalenes through Vinylcyclopropane Cyclopentene Rearrangement15 Functionalization of Bicyclo[3.3.0]octanes toward Chiral Dienes16 Miscellaneous Syntheses of Hydropentalenes17 Conclusion and Outlook

Sign in / Sign up

Export Citation Format

Share Document