Cyclic ether synthesis: sulfenyletherification with benzenesulfenyl chloride/N, N-diisopropylethylamine and sulfenate ester cycloadditions

1987 ◽  
Vol 65 (8) ◽  
pp. 1833-1837 ◽  
Author(s):  
Sudersan M. Tuladhar ◽  
Alex G. Fallis
Keyword(s):  
Cyclic Ether ◽  
Cyclic Ethers ◽  
Nucleophilic Displacement ◽  
Ether Synthesis ◽  
Special Case ◽  
General Method ◽  
Episulfonium Ion

A general method for the formation of the cyclic ethers 9, 10, 13, 14, 16, and 28 and the lactone 30 is described. The procedure employs benzenesulfenyl chloride prepared insitu in acetonitrile and N,N-diisopropylethylamine to generate a thiiranium (episulfonium) ion intermediate from which the cyclic products arise by internal nucleophilic displacement. In the special case of the norbornene alcohols 1 and 2 the oxetanes 5 and 6 are formed by intramolecular sulfenate ester cycloaddition.

Cyclic ether synthesis from diols using trimethyl phosphate

2017 ◽  
Vol 53 (35) ◽  
pp. 4787-4790 ◽  
Author(s):  
Shota Asai ◽  
Maho Kato ◽  
Yasunari Monguchi ◽  
Hironao Sajiki ◽  
Yoshinari Sawama
Keyword(s):  
Room Temperature ◽  
Cyclic Ether ◽  
Cyclic Ethers ◽  
Trimethyl Phosphate ◽  
Ether Synthesis

Cyclic ethers are simply synthesized from diols by using trimethyl phosphate at room temperature.

Participation of 19-substituents in electrophilic additions to 6,7-unsaturated 5α-cholestane and B-homo 5α-cholestane derivatives; A case of competition between the participation of an ambident neighboring group and external nucleophile attack

1980 ◽  
Vol 45 (2) ◽  
pp. 559-583 ◽  
Author(s):  
Pavel Kočovský ◽  
Ladislav Kohout ◽  
Václav Černý
Keyword(s):  
Perchloric Acid ◽  
Hydrobromic Acid ◽  
Cyclic Ether ◽  
Cyclic Ethers ◽  
Neighboring Group ◽  
Acid Cleavage ◽  
Neighbouring Group Participation ◽  
Aqueous Perchloric Acid ◽  
The Difference ◽  
Electrophilic Additions

Hypobromous acid action upon the 6,7-unsaturated 19-substituted 5α-cholestans Va-Vc results in the formation of two types of products, the cyclic ethers IX as products of 5(O)n participation of the 19-substituent, and the bromohydrins X. All these compounds are formed from the 6α,7α-bromonium ions Va'-Vc'. Under the same conditions the B-homo-5α-cholestane derivatives VIIa-VIIc afforded solely the cyclic ethers XIV as products of 5(O)n participation of the 19-substituent in the cleavage of the bromonium ions VIIa'-VIIc'. Acid cleavage of the 6α,7α-epoxides VIb and VIc with aqueous perchloric acid or hydrobromic acid gave two types of products, i.e. the cyclic ethers XI and the diols XII or bromohydrines XIII. The cyclic ethers XI arise by 5(O)n participation of the 19-substituent. The B-homo-6α, 7α-epoxide VIIIc on cleavage with aqueous perchloric acid have solely the cyclic ether XVc and by treatment with hydrobromic acid VIIIc afforded the mixture of XVc, as the main product, and of the bromohydrin XVIc. Discussed is the similarity of the bromonium ion cleavage with the fission of the corresponding epoxides, the mechanism of these reactions and the difference in the behaviour of the isomeric olefins Ia-c, IIIa-c, Va-c and VIIa-c and epoxides IIb,c, IVb,c, VIb,c and VIIIb,c. The competition between ambident neighbouring group participation and external nucleophile attack is discussed as well as the dependence of the products ratio on the nucleophilicity of the attacking species.

scholarly journals Thioether-Catalysed Tandem Synthesis of Furans and Cyclic Ethers or Lactones

Synlett ◽  
2017 ◽  
Vol 28 (11) ◽  
pp. 1358-1362 ◽  
Author(s):  
J. Clark ◽  
Verena Klaus
Keyword(s):  
Carboxylic Acid ◽  
Cyclic Ether ◽  
Single Step ◽  
Cyclic Ethers ◽  
The Creation ◽  
Tandem Synthesis

Acyclic conjugated ynenediones tethered to an alcohol or carboxylic acid are converted into furanyl-substituted cyclic ethers or lactones in a single step by treatment with the tetrahydrothiophene. Modest levels of diastereocontrol can be achieved in some cases where the presence of a substituent on the tether results in the creation of a second stereogenic centre upon formation of the cyclic ether or lactone.

scholarly journals C(sp3)-H alkenylation promoted by uranyl cation as a visible-light photocatalyst

2021 ◽  
Vol 2079 (1) ◽  
pp. 012020
Author(s):  
Zhiyu Feng
Keyword(s):  
Hydrogen Atom ◽  
Visible Light ◽  
Bond Formation ◽  
Cyclic Ether ◽  
Hydrogen Atom Transfer ◽  
Cyclic Ethers ◽  
Atom Transfer ◽  
Target Product ◽  
Visible Light Photocatalyst ◽  
Uranyl Cation

Abstract The alkenylation of cyclic ethers with β-nitroalkenes using uranyl cation as a photocatalyst is reported. Previous studies revealed the feasibility of incorporating organic photocatalyst in the visible light mediated alkenylation, while the uranyl cation serves as an alternative photocatalyst candidate successfully accomplish this transformation through a different pathway. The reaction features the direct hydrogen atom transfer (HAT) process to activate alpha C(sp3)-H of cyclic ether, and consequently cyclic ether is coupled with β-nitroalkene to give the target product with F-selectivity through C-C bond formation.

scholarly journals A Potentially Useful Procedure for Conversion of Ethers to Esters

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Li H ◽  
Mark Z ◽  
Graylion M ◽  
Shen T
Keyword(s):  
Building Blocks ◽  
Cyclic Ether ◽  
Gas Chromatography Mass Spectrometry ◽  
High Yield ◽  
Infrared Spectrometry ◽  
Cyclic Ethers ◽  
Efficient Procedure ◽  
Nuclear Magnetic Resonance Spectrometry ◽  
Magnetic Resonance Spectrometry ◽  
Reaction Processes

This communication reports a catalytic system for transformation of ethers into their corresponding esters, especially for cyclic ethers. This efficient procedure was developed as part of our efforts to synthesize nucleoside building blocks and their derivatives. Gas Chromatography-Mass Spectrometry (GC-MS) monitored the reaction processes, Nuclear Magnetic Resonance Spectrometry (NMR), and Infrared Spectrometry (IR) were used to verify the structure of the products. The conversions of Tetrahydrofuran (THF) and other cyclic ether into lactones were accomplished in high yield, over 95%. This approach could be extended too many types of ethers to produce directly corresponding esters simply. Four representatives of ethers were investigated. Cyclic ethers have the higher yields. Linear ethers gave lower yields. The reaction on methoxylcarbon or methyl ether carbon was not observed. The reacted catalyst can be reused over several times. For each reusing, only drops of sulfuric acid need to be added. Nevertheless, the asymmetric ethers selectivity needs to be addressed in future studies.

scholarly journals Products of Variables in Structural Equation Models: Multiplicative Reticular Action Models

2019 ◽  
Author(s):  
Steven M. Boker ◽  
Timo von Oertzen ◽  
Andreas Markus Brandmaier
Keyword(s):  
Latent Variables ◽  
Latent Variable ◽  
Structural Equation ◽  
Structural Equation Models ◽  
Equation Model ◽  
Random Coefficients ◽  
Action Model ◽  
Action Models ◽  
Special Case ◽  
General Method

A general method is introduced in which variables that are products of other variables in the context of a structural equation model (SEM) can be decomposed into the sources of variance due to the multiplicands. The result is a new category of SEM which we call a Multiplicative Reticular Action Model (XRAM). XRAM can include interactions between latent variables, multilevel random coefficients, latent variable moderators, and novel constructs such as factors of paths and twin genetic decomposition of multilevel random coefficients. The method relies on an assumption that all variance sources in a model can be decomposed into linear combinations of independent normal standardized variables. Although the distribution of a variable that is an outcome of multiplication between other variables is not normal, the assumption is that it can be decomposed into sources that are normal if one takes into account the non-normality induced by the multiplication. The method is applied to an example to show how in a special case it is equivalent to known unbiased and efficient estimators in the statistical literature. Two simulations are presented that demonstrate the precision of the approximation and implement the method to estimate parameters in a multilevel autoregressive framework.

scholarly journals IV. Mathematical contributions to the theory of evolution.—V. On the reconstruction of the stature of prehistoric races

1899 ◽  
Vol 192 ◽  
pp. 169-244 ◽  
Keyword(s):  
Lower Limbs ◽  
Long Bones ◽  
Upper Limbs ◽  
Theory Of Evolution ◽  
Remarkable Degree ◽  
The Mean ◽  
Standard Deviations ◽  
Special Case ◽  
General Method ◽  
Local Race

(1.) The object of this paper is to show, by the use of a special case as illustration, the true limits within which it is possible to reconstruct the parts of an extinct race from a knowledge of the size of a few organs or bones, when complete measurements have been or can be made for an allied and still extant race. The illustration I have taken is one of considerable interest in itself, and has been considered from a variety of standpoints by a long series of investigators. But I wish it to be considered purely as an illustration of a general method. What is here done for stature from long bones is equally applicable to other organs in Man. We might reconstruct in the same manner the dimensions of the hand from a knowledge of any of the finger bones, or the bones of the upper limbs from a knowledge of the bones of the lower limbs. Further, we need not confine our attention to Man, but can predict, with what often amounts to a remarkable degree of accuracy, the dimensions of the organs of one local race of any species from a knowledge of a considerable number of organs in a second local race, and of only one or two organs of the first. The importance of this result for the reconstruction of fossil or prehistoric races will be obvious. What we need for any such reconstruction are the following data:— ( a .) The mean sizes, the variabilities (standard-deviations), and the correlations of as many organs in an extant allied race as it is possible conveniently to measure. When the correlations of the organs under consideration are high ( e. g. , the long bones in Man), fifty to a hundred individuals may be sufficient; in other cases it is desirable that several hundred at least should be measured.

scholarly journals Polymerization of Cyclic Ethers Initiated by the Reaction of Cyclic Ether with Hexafluoropropylene Oxide.

2002 ◽  
pp. 365-369 ◽  
Author(s):  
Yasuyuki MASUBUCHI ◽  
Tokio HAGIWARA ◽  
Youichi IKEGAYA ◽  
Seiji KAWATA ◽  
Noriyuki YONEZAWA
Keyword(s):  
Cyclic Ether ◽  
Cyclic Ethers ◽  
Hexafluoropropylene Oxide

scholarly journals A New Variant of Fused Cyclic Ether Synthesis Based on Ireland-Claisen Rearrangement and RCM

2013 ◽  
Vol 8 (7) ◽  
pp. 1934578X1300800
Author(s):  
Daisuke Domon ◽  
Kenshu Fujiwara ◽  
Natsumi Kawamura ◽  
Ryo Katoono ◽  
Hidetoshi Kawai ◽  
...  
Keyword(s):  
Olefin Metathesis ◽  
Claisen Rearrangement ◽  
Cyclic Ether ◽  
Reaction Sequence ◽  
New Variant ◽  
Ether Synthesis

A new variant of fused cyclic ether synthesis based on Ireland-Claisen rearrangement and ring-closing olefin metathesis (RCM) was developed. The Ireland-Claisen rearrangement and ring-closing olefin metathesis (RCM) was developed. The Ireland-Claisen rearrangement of a ( Z)-3-alkoxyprop-2-en-1-yl glycolate ester having a cyclic ether on the oxygen at C3 of the ( Z)-prop-2-en-1-yl group stereoselectively produced an anti-α,β-dialkoxyester which was successfully transformed to a fused bicyclic ether via a reaction sequence including RCM.

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