Domino Wittig–Diels Alder reaction: synthesis of carbazole lignans

Tilve, Santosh G.; Torney, Prachi; Patre, Rupesh E.; Kamat, Durga P.; Srinivasan, Bikshandarkoil R.; Zubkov, Fedor I.

doi:10.1016/j.tetlet.2016.04.038

Cited by 8 publications

(8 citation statements)

References 34 publications

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“…A two-step synthesis of carbazole lignans from indole-2carboxaldehydes and cinnamyl-2-(triphenylphosphanylidene) acetates via Domino Wittig reaction/Diels-Alder reaction followed by aromatization in presence of DDQ was developed by S.G. Tilve and co-workers in 2016 (Scheme 16). [68] In the first step, the Wittig reaction between the indole-2-carboxaldehyde 1 and the phosphorane 108 led to the formation of the (E)-Scheme 15. Strategy for combining alkene hydroacylation and α-(hetero)arylation reactions.…”

Section: Synthetic Methodologies and Total Synthesismentioning

confidence: 99%

Indole‐2‐Carboxaldehyde: An Emerging Precursor for the Construction of Diversified Imperative Skeleton

2021

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Indole heterocycles constitute the structural framework of innumerable biologically active molecules and natural products having drug-like properties and other biochemical utilities. These compounds have been extensively studied by synthetic and medicinal chemists and various synthetic strategies have been established using indole-2-carboxaldehyde derivatives as a starting material. In this review we elaborately report indole-2-carboxaldehydes as a starting material for the synthesis of diversified indole scaffolds in the last decade (2010)(2011)(2012)(2013)(2014)(2015)(2016)(2017)(2018)(2019).

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Section: Synthetic Methodologies and Total Synthesismentioning

confidence: 99%

Indole‐2‐Carboxaldehyde: An Emerging Precursor for the Construction of Diversified Imperative Skeleton

2021

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“…38 Besides the synthesis of naturally occurring DNA topoisomerase II inhibitors, a number of investigations have been aimed at the development of their synthetic counterparts. [39][40][41] In particular, in one of the first studies, a onestep method was proposed for the synthesis of indole analogues of lignans possessing a furo[3,4-b]carbazole nucleus (Scheme 64). 39 According to the authors, ester 206 undergoes a thermal IMDAV cyclization to yield the desired adduct 207 (similar to isoelliptitoxin) in a mixture with isomer 208.…”

Section: Scheme 63 Synthesis Of the Ellipticine Core With The Aid Of mentioning

confidence: 99%

“…As a result, the procedure described above is applicable for the derivatization of 3-formylindole, giving rise to heterolignans 219, which are isomeric to compounds 218 (Scheme 67). 41 A formal IMDAV reaction has been observed during the study of a visible-light-promoted cyclization of dienes 220. 42 These silylvinylindoles underwent [4+2] cycloaddition in the presence of catalytic amounts of Ru(bpy) 3 (PF 6 ) 2 (a photosensitizer) and (NH 4 ) 2 S 2 O 8 (an oxidant) to offer the corresponding cyclopenta [b]carbazoles 221 (Scheme 68).…”

Section: Scheme 66 Indole-3-carboxaldehyde In the Domino Wittig/imdavmentioning

confidence: 99%

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

Krishna¹,

Grudinin²,

Nikitina³

et al. 2021

Synthesis

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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

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“…DDQ has also been used for benzylic dehydrogenation of lignan structures to olefins, and in some cases further aromatization to naphthalene type lignans [23,30,31,32]. One example of benzylic olefin formation is visualized in Scheme 4 by the DDQ oxidation of the natural lignan hydroxymatairesinol (HMR) [33,34].…”

Section: Non-metal-mediated Oxidationsmentioning

confidence: 99%

Oxidative Transformations of Lignans

Runeberg¹,

Brusentsev²,

Rendon³

et al. 2019

Molecules

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Numerous oxidative transformations of lignan structures have been reported in the literature. In this paper we present an overview on the current findings in the field. The focus is put on transformations targeting a specific structure, a specific reaction, or an interconversion of the lignan skeleton. Oxidative transformations related to biosynthesis, antioxidant measurements, and total syntheses are mostly excluded. Non-metal mediated as well as metal mediated oxidations are reported, and mechanisms based on hydrogen abstractions, epoxidations, hydroxylations, and radical reactions are discussed for the transformation and interconversion of lignan structures. Enzymatic oxidations, photooxidation, and electrochemical oxidations are also briefly reported.

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Domino Wittig–Diels Alder reaction: synthesis of carbazole lignans

Cited by 8 publications

References 34 publications

Indole‐2‐Carboxaldehyde: An Emerging Precursor for the Construction of Diversified Imperative Skeleton

Indole‐2‐Carboxaldehyde: An Emerging Precursor for the Construction of Diversified Imperative Skeleton

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

Oxidative Transformations of Lignans

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