Über Diensynthesen mit unsymmetrischen Addenden Butadien‐1‐carbonsäure‐(chlorid) und Acrylsäure‐(chlorid)

Alder, Kurt; Schumacher, Marianne; Wolff, Oswald

doi:10.1002/jlac.19495640202

Cited by 74 publications

(12 citation statements)

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“…Therefore, the results of and are in agreement with the experimental results and the predicted regioselectivities of and are obviously not consistent with the experimental results. [ 1‐8 ] In addition, both equilibrium geometry and reactivity index were also calculated by MP2 method, but the obtained regioselectivities were also not agreed with the experiments totally (Table S3).…”

Section: Results and Disccusionmentioning

confidence: 95%

“…Experimentally, in the reaction of a monosubstituted olefin with a 1‐substituted diene, predominance of ortho cycloadduct is to be expected. [ 1‐22 ] In this respect, the regioselectivities of the D‐A reactions of 1‐substituted dienes with unsymmetrical dienophile ( to 58) will be predicted according to the local HSAB principle. The local softness and the GLS were obtained by ab initio method at the level of MP2/6‐311++G(d,p) with the finite difference approximation (only at atomic level) and ABEEMσπ model (at both atomic and π‐bond levels), respectively.…”

Section: Results and Disccusionmentioning

confidence: 99%

“…These results are in good agreement with the experimental results. [ 1‐8 ]…”

Section: Results and Disccusionmentioning

confidence: 99%

“…Because of good regio‐ and stereoselectivity, D‐A reactions between unsymmetrical dienes and dienophiles have been studied in various experimental [ 1‐25 ] and theoretical methods. [ 24,26‐33 ] Especially, D‐A reactions in pericyclic reactions were gained widespread investigations by the conceptual density functional theory (CDFT).…”

Section: Background and Originality Contentmentioning

confidence: 99%

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Theoretical Investigation on Regioselectivities of Diels‐Alder Reactions by Conjugated Effect

Zhao

et al. 2020

Chin. J. Chem.

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of main observation and conclusion The regioselectivities of 76 Diels-Alder reactions between unsymmetrical dienes and dienophiles were investigated by local softness and generalized local softness at atomic and chemical bond view, respectively, where the reactivity descriptors were calculated by finite difference approximation and ABEEMσπ model. Based on local HSAB principle and matching criterion of local softness, reasonable explanation and prediction on regioselectivities of all reactions through ABEEMσπ model have been obtained, which are in agreement with the experimental results. Especially, at π-bond level, while the 1-substituents of dienes were NH2, NMe2, and NEt2, because of the p-π conjugated effect between the lone pairs of N atom and the conjugated π-bond of the four double-bonded carbon atoms in diene, it made the dienophile not easy to approach diene by Manner A, hence, Manner B can forecast the ortho regioisomer as main product well, and Manner A cannot. As to the other reactions, both Manner A and Manner B can predict their regioselectivities. It can be seen that the ABEEMσπ model can take the effect of the chemical environment on the reaction reactivity into account richly, especially the system includes π-bond and lone pairs. However, the results through the finite difference approximation are not reasonable. Background and Originality Content Diels-Alder (D-A) reaction is one of the most useful synthetic reactions, and its overwhelming importance is well known in organic synthesis of six-membered functionalized carbocyclic compounds. The usefulness of D-A reaction arises from its versatility and from its remarkable regio-and stereoselectivity. The reaction between unsymmetrical diene and dienophile can produce two isomeric adducts depending on the orientation of the substituents in the dienes, as shown in Figure 1.

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Section: Results and Disccusionmentioning

confidence: 95%

Section: Results and Disccusionmentioning

confidence: 99%

“…These results are in good agreement with the experimental results. [ 1‐8 ]…”

Section: Results and Disccusionmentioning

confidence: 99%

Section: Background and Originality Contentmentioning

confidence: 99%

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Theoretical Investigation on Regioselectivities of Diels‐Alder Reactions by Conjugated Effect

Zhao

et al. 2020

Chin. J. Chem.

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“…Cis and trans 4-cyclohexene-1 ,Zdicarboxylic acids (I) and Cis and trans 3-cyclohexene-1 ,ZdicarboxyZic acids (11) In contrast to the behaviour of cis and trans cyclohexane-1 ,2-dicarboxylic acids? wherein marked differences in the mass spectra were observed, the mass spectra of I I the cis and trans isomers of (I) are closely similar, as are those of the cis and truns isomers of (11).…”

Section: Resultsmentioning

confidence: 99%

The mass spectra of carboxylic acids—V: Carboxyl‐carboxyl interaction in the fragmentation of some cycloalkene‐1,2‐dicarboxylic acids

Benoit

Holmes

1972

Org. Mass Spectrom.

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The fragmentation mechanisms of the six isomeric cyclohexene-l,2-dicarboxylic acids are discussed. Only the 1-cyclohexene acid, by virtue of the major sequential losses of H,O and C 0 2 from the molecular ion, is readily distinguishable from its isomers, all of whose mass spectra are closely similar. In contrast to cis and trans cyclohexane-l,2-dicarboxylic acids, whose mass spectra were markedly different, the cis and trans cyclohexene-l,2-dicarboxylic acids fragment in a similar fashion. The mass spectra of l-cyclopentene-l,2-dicarboxylic acid and l-cyclobutene-l,2-dicarboxylic acid also exhibit a strong carboxyl-carboxyl interaction; the fragmentation behaviour of the 1-cyclopenteneacid is, however, more complex than that of the 1-cyclohexene and 1-cyclobutene acids.

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Isoprene Polymers

Senyek

2008

Encyclopedia of Polymer Science and Technology

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Isoprene was first isolated from the pyrolysis products of natural rubber. The first preparation of polyisoprene was reported in 1879. In 1950, the goal of preparing synthetic cis 1,4‐polyisoprene as a counter part to natural rubber was achieved. Attention was then focused on commercial preparation of isoprene for polymerization use. Shortly after the discovery of stereospecific catalysts, the first commercial polyisoprene plant came on stream in 1959–1960 using a lithium catalyst. Isoprene is a reactive diene that undergoes cycloaddition, electrophilic, nucleophilic, free‐radical, and coordinated catalytic addition, and thermal dimerization. Information on the production of isoprene by naphtha cracking as well as the synthetic processes is detailed. Depending on the catalyst and conditions, isoprene may undergo 1,2,3,4, or 1,4 addition leading to several isomeric structures. Coordination catalysts, alkali metal catalysts, and Alfin catalysts are important for polymerization and are discussed. Chemical modification of polymers is a convenient way of altering physical and mechanical properties. Highly unsaturated polymers such as polyisoprene are easily modified because the olefinic bond is readily available. Their high reactivity with a variety of chemical substances offers advantages in chemical modification and vulcanization. However, reaction with oxygen and ozone causes degradation and loss of physical and mechanical properties. Synthetic polyisoprene is processed on conventional rubber machinery. Compounding technology is similar to that used for natural rubber. Typical formulations are given. A brief discussion of isoprene copolymers and 1,4‐ trans ‐polyisoprene is included. Isoprene is classified as a flammable liquid. It is a moderate irritant to the skin, eyes, and mucous membranes. The primary use for cis ‐1,4‐polyisoprene is in tires and tire products. It is also used, eg, in molded and mechanical goods, adhesives, belts, foam rubber, and elastic threads.. Automotive molded products and medical applications are typical. Trans ‐1,4‐Poyisoprene can be extracted, calendered, injection molded, and compression molded. It can be used in blends with other polymers. Its main use is in golf ball covers.

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Über Diensynthesen mit unsymmetrischen Addenden Butadien‐1‐carbonsäure‐(chlorid) und Acrylsäure‐(chlorid)

Cited by 74 publications

References 10 publications

Theoretical Investigation on Regioselectivities of Diels‐Alder Reactions by Conjugated Effect

Theoretical Investigation on Regioselectivities of Diels‐Alder Reactions by Conjugated Effect

The mass spectra of carboxylic acids—V: Carboxyl‐carboxyl interaction in the fragmentation of some cycloalkene‐1,2‐dicarboxylic acids

Isoprene Polymers

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