Synthese von Heterocyclen durch CC‐Knüpfung. IV. Heterocyclensynthesen durch intramolekulare Dien‐Reaktion

Schmitz, Ernst; Heuck, Uwe; Preuschhof, Helmut; Gründemann, E.

doi:10.1002/prac.19823240413

Cited by 4 publications

(5 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Heating of amides 271 up to 230 °C leads to cycloadducts 272 in poor to moderate yields (Scheme 84 ). 4 The presence of a methyl group at the α-position relative to the carbonyl group prevents the IMDAV reaction of 271g , and product 272g is not formed. In contrast, the introduction of donor alkyl groups into the dienophilic fragment does not interfere with the intramolecular cycloaddition of cyclohexene 273 .…”

Section: Imdav Reactions Of Styrenes and Vinylnaphthalenesmentioning

confidence: 99%

“…It should be mentioned that the relative configurations of the asymmetric centers in the resulting heterocycles 272 and 274 were not reliably determined in the published work. 4…”

Section: Imdav Reactions Of Styrenes and Vinylnaphthalenesmentioning

confidence: 99%

“…2a-h The first studies on the topic of styrenes by Gopinath, appeared in print between 1963-1966, 3 but did not draw much attention from scientists, and it was not until the beginning of the eighties that convincing and synthetically attractive reports on the successful involvement of styrenes and 2-vinylfuran derivatives in IMDA reactions were published (Scheme 1). [4][5][6] This is related to the fact that in the transition state of the IMDA reaction (for example, the intermediate B) (Scheme 2), the aromaticity of the aromatic ring is broken, and in addition, there is no conju-Hence, taking into account the aforementioned features as well as the usually high levels of chemo-and diastereoselectivity, the transformations described above can be distinguished as a separate class of Diels-Alder reaction: the IntraMolecular Diels-Alder Vinylarene reaction (i.e., the IMDAV reaction).…”

Section: Introductionmentioning

confidence: 99%

“…The first studies on the topic of styrenes by Klemm and Gopinath, appeared in print between 1963–1966, 3 but did not draw much attention from scientists, and it was not until the beginning of the eighties that convincing and synthetically attractive reports on the successful involvement of styrenes and 2-vinylfuran derivatives in IMDA reactions were published (Scheme 1 ). 4 5 6 This is related to the fact that in the transition state of the IMDA reaction (for example, the intermediate B ) (Scheme 2 ), the aromaticity of the aromatic ring is broken, and in addition, there is no conjugation between the exocyclic double bond and the aromatic nucleus. Obviously, as a consequence of this, the activation energy of the entire process (the conversion of A into B ) increases, which requires the application of harsh reaction conditions in comparison with other types of Diels–Alder reaction (heating, often higher than 200 °C, microwave irradiation, or catalysis).…”

Section: Introductionmentioning

confidence: 99%

“…The reaction proceeds through the same intermediates (55,56), and regardless of the substituents R 1 -R 4 , the chemo-and diastereoselectivity of the cycloaddition is maintained at a high level even at 140 °C, whilst the yields of products 57 range from low to moderate (Table 2).…”

mentioning

confidence: 99%

See 4 more Smart Citations

IntraMolecular Diels–Alder Reactions of Vinylarenes and Alkynyl Arenes (the IMDAV Reaction)

Krishna¹,

Grudinin²,

Nikitina³

et al. 2021

Synthesis

View full text Add to dashboard Cite

This comprehensive review summarizes the published literature data concerning the intramolecular Diels–Alder reactions of vinylarenes (the IMDAV reaction) and alkynyl arenes from 1970 to 2019, and covers mainly intramolecular [4+2] cycloaddition reactions of vinyl- or acetylene-substituted furans, thiophenes, pyrroles, indoles, imidazoles, benzenes, and naphthalenes, in which the unsaturated substituent is linked directly to an arene moiety. The selected area of the Diels–Alder reaction differs from other forms of [4+2] cycloadditions due to the uniqueness of the diene fragment, which, along with an exocyclic multiple bond, includes the double bond of an aromatic or heteroaromatic nucleus in its system. Thus, during the formation of the [4+2] cycloaddition intermediate, the aromaticity of furan, thiophene and even benzene rings is broken, leading, as a rule, to the formation of heterocyclic structures rarely accessible by other methods, in contrast to the majority of intermolecular Diels–Alder reactions, with the highest degree of chemo-, regio-, and diastereoselectivity. Therefore, the IMDAV approach is often used for the synthesis of naturally occurring and bioactive molecules, which are also discussed in this review alongside other applications of this reaction. Whenever possible, we have tried to avoid examples of radical, photochemical, oxidative, precious-metal-complex-catalyzed cyclizations and other types of formal [4+2] cycloadditions, focusing on thermal Diels–Alder reactions in the first step, according to the classical mechanism. The second stage of the process, aromatization, is unique for many initial substrates, and hence considerable attention in this overview is given to the detailed description of the reaction mechanisms.1 Introduction2 IMDAV Reactions of Vinylfurans2.1 Alkenes as Internal Dienophiles2.2 Alkynes and Allenes as Internal Dienophiles3 IMDAV Reactions of Vinylthiophenes3.1 Alkenes as Internal Dienophiles3.2 Alkynes as Internal Dienophiles4 IMDAV Reactions of Vinylbenzothiophenes5 IMDAV Reactions of Vinylpyrroles6 IMDAV Reactions of Vinylindoles6.1 Alkenes as Internal Dienophiles6.2 Alkynes as Internal Dienophiles7 IMDAV Reactions of Styrenes and Vinylnaphthalenes7.1 Alkenes as Internal Dienophiles7.2 Alkynes as Internal Dienophiles7.3 Alkynes as Internal Dienophiles in Aryl Acetylenes (the Intramolecular Dehydro Diels–Alder Reaction)8 IMDAV Reactions of Vinylimidazoles, Vinylisoxazoles and Vinylpyridines9 Conclusion10 Abbreviations

show abstract

Section: Imdav Reactions Of Styrenes and Vinylnaphthalenesmentioning

confidence: 99%

“…It should be mentioned that the relative configurations of the asymmetric centers in the resulting heterocycles 272 and 274 were not reliably determined in the published work. 4…”

Section: Imdav Reactions Of Styrenes and Vinylnaphthalenesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

IntraMolecular Diels–Alder Reactions of Vinylarenes and Alkynyl Arenes (the IMDAV Reaction)

Krishna¹,

Grudinin²,

Nikitina³

et al. 2021

Synthesis

View full text Add to dashboard Cite

show abstract

The IntramolecularDiels–Alder Reaction

Ciganek

1984

Organic Reactions

108

View full text Add to dashboard Cite

The Diels–Alder reaction is one of the most useful reactions available to the synthetic organic chemist. It is thus surprising that the intramolecular version, in which both diene and dienophile are part of the same molecule, remained virtually unexplored for many years. Early examples were often the result of unexpected observations, and the many advantages of this reaction were recognized and put to use in the synthesis of complex polycyclic molecules only recently. In the intramolecular Diels–Alder reaction, two rings are formed in one step. In addition to the six‐membered ring formed by the [4 + 2]cycloaddition, the product contains a second ring, the size of which depends on the length of the chain connecting diene and dienophile. Of the two possible regiochemical modes of addition, that leading to the fused product usually predominates to the virtual exclusion of the bridged product. The Diels–Alder reaction proceeds through a highly ordered transition state that is reflected in large negative activation entropies. In the intramolecular version, some of the ordering has been accomplished in advance by making the two reacting functionalities part of the same molecule. This results in less negative activation entropies and increased reaction rates under often surprisingly mild conditions. On the other hand, by using forcing conditions one can sometimes carry out intramolecular Diels–Alder additions that would be doomed to failure in the intermolecular version. Lower reaction temperatures, together with the constraints imposed by the connecting chain, often result in pronounced regio‐ and stereoselectivity. Side reactions such as dimerization or polymerization can be avoided by using high dilution or low pressures in the gas phase. Examples where the bimolecular Diels–Alder reaction interferes with the intramolecular cyclization are rare. All of these features suggest that the intramolecular Diels–Alder reaction should be considered for any synthesis of a molecule containing a six‐membered ring fused to a second ring, especially if that ring is five‐ or six‐membered. Such a synthetic scheme may be made convergent by building up the diene and dienophile portions separately and connecting them just prior to the actual cyclization. Another potential use of the intramolecular Diels–Alder reaction that has not received much attention to date is as a supplement to the intermolecular Diels–Alder reaction in cases where the latter is unsuccessful or gives the wrong regio‐ or stereochemistry. By judicious choice of the connecting chain, the reaction may be made to proceed with the desired selectivity; this is followed by cleavage of the chain and conversion of the two ends to the desired functionalities. Once the feasibility of employing the intramolecular Diels–Alder reaction has been recognized, the main challenge often becomes the preparation of the substrate. A discussion of that aspect is beyond the scope of this chapter; however, by scanning the tables for the particular diene, dienophile, and chain one is interested in, and then referring to the original literature, it will often be possible to obtain some indications on how to proceed. An attempt has been made to cover the literature of the thermal intramolecular Diels–Alder reaction as completely as possible up to and including the year 1981. Many of the papers that appeared in 1982 and some from 1983 have also been included. More recent references are given in an addendum at the end of the tabular survey.

show abstract

ChemInform Abstract: SYNTHESIS OF HETEROCYCLIC COMPOUNDS BY CARBON‐CARBON BOND CLOSURE. IV. SYNTHESIS OF HETEROCYCLIC COMPOUNDS BY INTRAMOLECULAR DIENE REACTION

Schmitz¹,

Heuck²,

Preuschhof³

et al. 1982

Chemischer Informationsdienst

View full text Add to dashboard Cite

show abstract

Synthese von Heterocyclen durch CC‐Knüpfung. IV. Heterocyclensynthesen durch intramolekulare Dien‐Reaktion

Cited by 4 publications

References 11 publications

IntraMolecular Diels–Alder Reactions of Vinylarenes and Alkynyl Arenes (the IMDAV Reaction)

IntraMolecular Diels–Alder Reactions of Vinylarenes and Alkynyl Arenes (the IMDAV Reaction)

The IntramolecularDiels–Alder Reaction

ChemInform Abstract: SYNTHESIS OF HETEROCYCLIC COMPOUNDS BY CARBON‐CARBON BOND CLOSURE. IV. SYNTHESIS OF HETEROCYCLIC COMPOUNDS BY INTRAMOLECULAR DIENE REACTION

Contact Info

Product

Resources

About