Ring Opening Of Cyclic Ethers Research Articles

Site and Structural Requirements for the Dehydra-Decyclization of Cyclic Ethers on ZrO2

In this study, we examined the site and structural requirements for the dehydra-decyclization of cyclic ethers, tetrahydrofuran, and tetrahydropyran to produce conjugated dienes over ZrO2-based catalysts, a reaction that could be an important step in the use of biomass-derived sugars as a starting material to produce monomers for the plastics industry. To help identify the active sites for this reaction, studies were conducted in which ZrO2 surfaces were decorated with Na. These studies showed that Na was effective at poisoning the activity for the ring opening of cyclic ethers, but much less so for the dehydration of the resulting adsorbed alkoxides. The studies of the activity of different types of ZrO2 for the dehydra-decyclization reaction, including single crystals and ultra-thin films supported on MgAl2O4 and silica, also showed that the reaction was dependent on the local structure of the ZrO2 surface. The insights these results provide for identifying the active sites on the ZrO2 surface are discussed.

Visible-Light Mediated Oxidative Fragmentation of Ethers and Acetals by Means of Fe(III) Catalysis.

A new method employing iron(III) acetylacetonate along with visible light is described to effect oxidative ring opening of cyclic ethers and acetals with unparalleled efficiency. The method allows for a photocatalytic radical chemistry approach to functionalize relatively inert cyclic ethers into useful synthetic intermediates. The methodology sheds further light on the use of underexplored iron complexes in visible-light photochemical contexts and illustrates that simple Fe(III) complexes can initiate redox processes from 4LMCT excited states.

A visible light-mediated three-component strategy based on the ring-opening of cyclic ethers with aryldiazoacetates and nucleophiles

A visible light-mediated strategy insensitive to air or moisture allows a 3-component reaction between aryldiazoacetates, cyclic ethers and various nucleophiles to afford formal O–H inserted products of more complex alcohols.

Catalytic Reduction of Cyclic Ethers with Hydrosilanes

Catalytic reductive transformations of ethers as a synthetic building block are an important class of chemical reactions because a range of essential chemical feedstocks and fuels in contemporary life can be prepared through the key step of ethereal C-O bond cleavage of cellulosic biomass. Although conventional stoichiometric and catalytic methods for sp2 - and sp3 -C-O bond cleavage of linear ethers and alcohols with hydrosilanes are well established, silylative ring opening of cyclic ethers has been less highlighted in this context. This review outlines catalytic systems for the silylative reduction of a range of cyclic ethers, including epoxides and sugars, leading to the corresponding alcohols and/or hydrocarbons. The chemical reactivity and selectivity of these ring-opening catalytic processes are discussed with respect to the type of substrates; the representative catalytic working modes are also described.

Ring-opening of cyclic ethers by aluminum hydridotriphenylborate.

Molecular aluminum hydride [(L)AlH2] (L = Me3TACD) reacted with 2 equiv. of BPh3 in THF or THP to give the cationic alkoxides [(L)Al(OR)][HBPh3] (R = nBu, nPent) by facile ring-opening of the cyclic ethers. The Cα-O bond cleavage which involves the isolable intermediate [(L)AlH][HBPh3] is a result of hydride transfer to Cα from [HBPh3]-.

Ring-opening of cyclic ethers with carbon–carbon bond formation by Grignard reagents

The ring-opening of cyclic ethers with concomitant C–C bond formation was studied with a number of Grignard reagents. The transformation was performed in a sealed vial by heating to ∼160 °C in an aluminum block or at 180 °C in a microwave oven. Good yields of the product alcohols were obtained with allyl- and benzylmagnesium halides when the ether was tetrahydrofuran or 3,3-dimethyloxetane. Lower yields were obtained with substituted tetrahydrofurans while no ring-opening was observed with tetrahydropyran. Only highly reactive allyl and benzyl Grignard reagents participated in the transformation while no reaction occurred with other alkylmagnesium halides.

ChemInform Abstract: Ring Opening of Cyclic Ethers by Sulfuric Acid—Acetic Anhydride.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Ring opening of cyclic ethers by sulfuric acid ‐ acetic anhydride

AbstractCyclic ethers such as tetrahydrofuran or tetrahydropyran were easily cleaved at room temperature by sulfuric acid ‐ acetic anhydride providing the corresponding diacetoxyalkanes in good yield. The ring opening was applicable to saturated cyclic ethers, regardless of the presence of substituent groups.

ChemInform Abstract: Formation of Iodohydrins by Ring Opening of Cyclic Ethers by Samarium(II) Iodide in Benzene‐hexamethylphosphoramide in the Presence of Boron Trifluoride Diethyl Etherate.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Introduction of Alkyl- or Phenylseleno Group by the Ring Opening of Cyclic Ethers Using Dialkyl- or Alkylphenylselenium Dibromide and Sodium Borohydride

Abstract The reaction of dialkyl- or alkylphenylselenium dibromide with cyclic ethers in the presence of sodium borohydride gave ω-hydroxyalkyl alkyl or phenyl selenides as the ring opening products of the cyclic ethers.

Cyclische Ether als Edukte zur Synthese von Schmetterlings-Pheromonen

ω-Iodo(trialkylsiloxy)alkanes 2 prepared by ring opening of cyclic ethers with iodotrimethylsilane, are useful starting materials for the synthesis of pheromone components. Reaction with triphenylphosphine to give the corresponding Wittig reagent and subsequent coupling with lithium (Z)-dihex-1-enylcuprate gives (Z)-alken-1-ols 5 and 7, after deprotection, in good yields. The direct coupling of 2 with alkynes failed because of competition reactions.

Regioselective ring opening of unsymmetrical cyclic ethers with the A1C13-NaI-acetonitrile system: Application to hydroxylation of ent-kaurene.

Abstract Unsymmetrically substituted 5-membered cyclic ethers were effectively cleaved with the A1C1 3 -NaI-CH 3 CN system at the less hindered carbon atom to afford δ-iodoalcohols. Conversion of ent -kaurene to ent -14α- and ent -12β-hydroxykaurene was achieved through the ring opening of the cyclic ether with the present system as a key step.

The Chemistry of Carbonyl Chloride Fluoride. I. The Ring Opening of Cyclic Ethers with Carbonyl Chloride Fluoride

The Chemistry of Carbonyl Chloride Fluoride. I. The Ring Opening of Cyclic Ethers with Carbonyl Chloride Fluoride