Active Copper Catalyzed Regioselective Ring Opening of Epoxides by Heterocyclic Amines: An Efficient Protocol for Synthesis of β-Amino Alcohols

2019 ◽  
Vol 4 (3) ◽  
pp. 194-199
Author(s):  
Santosh S. Devkate ◽  
Arvind S. Burungale ◽  
Ashok S. Pise ◽  
Sunil D. Jadhav
Keyword(s):  
Natural Products ◽  
Carbon Atom ◽  
Ring Opening ◽  
Amino Alcohols ◽  
Heterocyclic Amines ◽  
Epoxide Ring ◽  
Epoxide Ring Opening ◽  
Ring Opening Of Epoxide ◽  
Ring Opening Of Epoxides

The regioselective epoxide ring opening at less substituted carbon atom of epoxide were reported by nucleophiles like heterocyclic amines which gives well known 1,2-difunctionalized amino alcohols. These are present in many synthetic as well as natural products. The ring opening of epoxide is achieved by cleavage with amines in presence of copper(0) as a catalyst. It is observed that the lithium napthalenide reduction of copper(I) produces a highly reactive form of copper(0) that acts as a catalyst for ring opening of epoxides with an amine.

scholarly journals 1-Tosyl-6-vinyl-4,5,6,7-tetrahydro-1H-benzo [d] imidazole-2-amine

Molbank ◽  
10.3390/m1262 ◽  
2021 ◽  
Vol 2021 (3) ◽  
pp. M1262
Author(s):  
Fiach B. Meany ◽  
Sarah O’Rourke ◽  
Paul V. Murphy
Keyword(s):  
Natural Products ◽  
Nmr Spectroscopy ◽  
1H Nmr ◽  
13C Nmr ◽  
Title Compound ◽  
Ring Opening ◽  
13C Nmr Spectroscopy ◽  
Amino Alcohols ◽  
Epoxide Ring ◽  
Epoxide Ring Opening

The alkene functionalised 2-aminobenzimidazole ring found in terrazoanthine natural products was synthesized in 3 steps from 1,2-epoxy-4-vinylcyclohexane via epoxide ring opening with toluenesulphonamide yielding 2 regioisomeric, separable amino alcohols. One isomer was oxidized to the corresponding ketone and subsequently condensed with cyanamide to furnish the title compound, which was characterized by 1H-NMR and 13C-NMR spectroscopy.

scholarly journals Synthetic and biosynthetic methods for selective cyclisations of 4,5-epoxy alcohols to tetrahydropyrans

2022 ◽  
Author(s):  
James I. Bowen ◽  
Luoyi Wang ◽  
Matthew P. Crump ◽  
Christine L. Willis
Keyword(s):  
Natural Products ◽  
Ring Opening ◽  
Epoxide Ring ◽  
Biosynthetic Pathways ◽  
Epoxide Ring Opening ◽  
Epoxy Alcohols

In this review, methods for the selective intramolecular epoxide ring opening (IERO) of 4,5-epoxy-alcohols are discussed as well as biosynthetic pathways to tetrahydropyran-containing natural products which utilise IERO reactions.

scholarly journals Theoretical Study on Epoxide Ring-opening in CO2/Epoxide Copolymerization Catalyzed by Bifunctional Salen-Type Cobalt(III) Complexes: Influence of Stereoelectronic Factors

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 328
Author(s):  
Karol Dyduch ◽  
Aleksandra Roznowska ◽  
Monika Srebro-Hooper ◽  
Bun Yeoul Lee ◽  
Artur Michalak
Keyword(s):  
Carbon Atom ◽  
Ring Opening ◽  
Density Functional ◽  
Model Systems ◽  
Conformational Space ◽  
Nucleophilic Attack ◽  
Epoxide Ring ◽  
Epoxide Ring Opening ◽  
The Real ◽  
Ring Opening Reaction

Propylene oxide (PO) binding and ring-opening reaction with the bifunctional CO2/epoxide copolymerization catalyst, based on the Co(III)-salcy complex including two quaternary ammonium salts with n-butyl substituents (N+-chains) were investigated by Density Functional Theory (DFT) calculations and compared with the model systems without the N+-chains. The importance of the different possible stereoisomers and the stereoselectivity of these processes for (S)- and (R)-enantiomers of PO were considered. To explore the conformational space for the real catalyst, a complex approach, developed previously was applied. The calculations for the model systems directly demonstrate that PO-ring opening proceeds preferentially in trans catalysts’ configuration and no participation of cis-β isomers is viable; nucleophilic attack at the methylene-carbon atom is preferred over that at methine-carbon atom. For the real bifunctional catalyst, with the (S,S)-configuration of cyclohexane, the results indicate a preference of (R)-PO ring-opening over (S)-PO ring-opening (ca. 6:5). Concerning stereoisomers resulting from the orientation of N+-chains in the real catalyst, different groups of structures participate in the ring-opening reaction for (R)-PO, and different for (S)-PO. The high population of nonreactive complexes of (R)-PO may be the key factor responsible for decreasing the activity of the analyzed catalyst in the epoxide ring-opening reaction.

Aluminium triflate as catalyst for epoxide ring-opening and esterification reactions — Mechanistic aspects

2005 ◽  
Vol 83 (6-7) ◽  
pp. 854-861 ◽  
Author(s):  
Yvette M Terblans ◽  
Johannes J Huyser ◽  
Michelle Huyser ◽  
Michael J Green ◽  
Desmond A Young ◽  
...  
Keyword(s):  
Ring Opening ◽  
Epoxide Ring ◽  
Epoxide Ring Opening ◽  
Low Concentrations ◽  
Ring Opening Reactions ◽  
Ring Opening Of Epoxides ◽  
Molecular Modeling Studies ◽  
Esterification Reactions ◽  
Active Intermediates ◽  
Formation Energies

Al(CF3SO3)3 is a highly effective catalyst for the ring opening of epoxides with methanol, as well as for the esterification of carboxylic acids with alcohols. Factors that influence the rate of the ring opening of butene oxide with methanol and the esterification of acetic acid with n-propanol and ethanol were investigated. It was found that low concentrations (e.g., ~5 ppm) of Al(CF3SO3)3 catalyze the ring-opening reactions, whereas considerably higher concentrations are required for esterification reactions. Molecular modeling studies suggest that these differences can be rationalized in terms of the formation energies of the active intermediates of these reactions.Key words: epoxide, ring opening, esterification, aluminium triflate.

Bimetallic Radical Redox-Relay Catalysis for the Isomerization of Epoxides to Allylic Alcohols

2019 ◽  
Author(s):  
Ke-Yin Ye ◽  
Terry McCallum ◽  
Song Lin
Keyword(s):  
Ring Opening ◽  
High Reactivity ◽  
Hydrogen Atom Transfer ◽  
Organic Radicals ◽  
Epoxide Ring ◽  
Allylic Alcohols ◽  
Epoxide Ring Opening ◽  
Bond Forming ◽  
Co Catalysts ◽  
The Rich

Organic radicals are generally short-lived intermediates with exceptionally high reactivity. Strategically, achieving synthetically useful transformations mediated by organic radicals requires both efficient initiation and selective termination events. Here, we report a new catalytic strategy, namely bimetallic radical redox-relay, in the regio- and stereoselective rearrangement of epoxides to allylic alcohols. This approach exploits the rich redox chemistry of Ti and Co complexes and merges reductive epoxide ring opening (initiation) with hydrogen atom transfer (termination). Critically, upon effecting key bond-forming and -breaking events, Ti and Co catalysts undergo proton-transfer/electron-transfer with one another to achieve turnover, thus constituting a truly synergistic dual catalytic system.<br>

Construction the A-B bicyclic ring structure of Stemocurtisisne

2020 ◽  
Vol 17 ◽  
Author(s):  
Duc Dau Xuan
Keyword(s):  
Glutamic Acid ◽  
Natural Product ◽  
Mannich Reaction ◽  
Boronic Acid ◽  
Ring Opening ◽  
Ring Structure ◽  
Starting Material ◽  
Epoxide Ring ◽  
Epoxide Ring Opening

: The synthesis of the A-B bicyclic ring structure 3 of the natural product Stemocurtisine is described. The synthesis was accomplished in seven synthetic steps from commercially available L-glutamic acid. The key step involved a borono-Mannich reaction between the hemiaminal 6 and trans-β-styryl boronic acid and trans-β-styrylpotassiumtrifluoroborate to prepare the cis diene 4. Attempts to prepare the A-B-C ring compound 2 via intramolecular epoxide ring opening followed by rearangement under different basic conditions were unsuccessful. Only unreactive starting material was recovered.

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