An Approach to One‐Pot Regioselective Synthesis of Indenones through Palladium‐Catalyzed Annulation in Water

Ramesh, Karu; Satyanarayana, Gedu

doi:10.1002/ejoc.201800591

Cited by 25 publications

(4 citation statements)

References 68 publications

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“…The key building blocks are the diketones 9 and 13 , which were prepared by palladium-catalyzed annulation of 1,2-diphenylacetylene onto the 3,7-dibromonaphthalene-2,6-dicarbaldehyde 8 and 1,5-dibromonaphthalene-2,6-dicarbaldehyde 12 , respectively (Scheme ). 8 was obtained via bromination, esterification, and reduction, followed by oxidation from 2,6-naphthalenedicarboxylic acid.…”

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confidence: 99%

Antiaromatic Dicyclopenta[b,g]/[a,f]naphthalene Isomers Showing an Open-Shell Singlet Ground State with Tunable Diradical Character

Han

Shen

et al. 2021

J. Am. Chem. Soc.

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Since the first isolation of 1,3,5,7-tetra-tert-butyl-s-indacene in 1986, core-expanded s- and as-indacenes have attracted intensive interest. However, there is no reported synthesis of such type of molecules due to their high reactivity for over 30 years. Herein, we report the successful synthesis of two relatively stable, core-expanded indacene isomers, dicyclopenta[b,g]-naphthalene (5) and dicyclopenta[a,f]naphthalene (6). X-ray crystallographic analyses reveal that the backbone of 5 adopts a bond-delocalized structure, while that of 6 exhibits a bond-localized character. Variable-temperature 1H NMR/ESR measurements, electronic absorption spectra, and theoretical calculations confirm that both molecules are globally antiaromatic and have an open-shell singlet ground state. However, 6 shows stronger antiaromaticity, a larger diradical character (y 0 = 48%), and a smaller singlet–triplet energy gap (ΔE S‑T = −0.99 kcal mol–1) compared to 5 (y 0 = 30%, ΔE S‑T = −6.88 kcal mol–1), which can be explained by their different quinoidal structures.

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confidence: 99%

Antiaromatic Dicyclopenta[b,g]/[a,f]naphthalene Isomers Showing an Open-Shell Singlet Ground State with Tunable Diradical Character

Han

Shen

et al. 2021

J. Am. Chem. Soc.

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“…A similar cyclization of 3,3-diarylpropanenitriles into 3-arylindanones in TfOH was described by us previously [17]. It should be specially emphasized that the synthesis of indenones is an important goal in organic chemistry since this structural motif is associated with interesting chemical and biological properties [27][28][29][30][31][32]. We also conducted reactions of nitriles 1a-c with arenes in TfOH at room temperature, which, however, led to complex mixtures of reaction products.…”

Section: Resultsmentioning

confidence: 60%

AlBr₃-Promoted stereoselective anti-hydroarylation of the acetylene bond in 3-arylpropynenitriles by electron-rich arenes: synthesis of 3,3-diarylpropenenitriles

Gorbunova

Ryabukhin

Vasilyev

2021

Beilstein J. Org. Chem.

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Reactions of 3-arylpropynenitriles (ArC≡CCN) with electron-rich arenes (Ar′H, benzene and its polymethylated derivatives) under the action of aluminum bromide (AlBr3, 6 equiv) at room temperature for 0.5–2 h result in the stereoselective formation of 3,3-diarylpropenenitriles (Ar(Ar′)C=CHCN) in yields of 20–64%, as products of mainly anti-hydroarylation of the acetylene bond. The obtained 3,3-diarylpropenenitriles in triflic acid CF3SO3H (TfOH) at room temperature for 1 h are cyclized into 3-arylindenones in yields of 55–70%.

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“…The excellent regioselectivity allowed this reaction to serve as a key step in the synthesis of a neolignan (Scheme 15, bottom). 28…”

Section: Intermolecular Reactionsmentioning

confidence: 99%

Recent Advances in Palladium-Catalyzed Bridging C–H Activation by Using Alkenes, Alkynes or Diazo Compounds as Bridging Reagents

et al. 2020

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Transition-metal-catalyzed direct inert C–H bond functionalization has attracted much attention over the past decades. However, because of the high strain energy of the suspected palladacycle generated via C–H bond palladation, direct functionalization of a C–H bond less than a three-bond distance from a catalyst center is highly challenging. In this short review, we summarize the advances on palladium-catalyzed bridging C–H activation, in which an inert proximal C–H bond palladation is promoted by the elementary step of migratory insertion of an alkene, an alkyne or a metal carbene intermediate.1 Introduction2 Palladium-Catalyzed Alkene Bridging C–H Activation2.1 Intramolecular Reactions2.2 Intermolecular Reactions3 Palladium-Catalyzed Alkyne Bridging C–H Activation3.1 Intermolecular Reactions3.2 Intramolecular Reactions4 Palladium-Catalyzed Carbene Bridging C–H Activation5 Conclusion and Outlook

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An Approach to One‐Pot Regioselective Synthesis of Indenones through Palladium‐Catalyzed Annulation in Water

Cited by 25 publications

References 68 publications

Antiaromatic Dicyclopenta[b,g]/[a,f]naphthalene Isomers Showing an Open-Shell Singlet Ground State with Tunable Diradical Character

Antiaromatic Dicyclopenta[b,g]/[a,f]naphthalene Isomers Showing an Open-Shell Singlet Ground State with Tunable Diradical Character

AlBr₃-Promoted stereoselective anti-hydroarylation of the acetylene bond in 3-arylpropynenitriles by electron-rich arenes: synthesis of 3,3-diarylpropenenitriles

Recent Advances in Palladium-Catalyzed Bridging C–H Activation by Using Alkenes, Alkynes or Diazo Compounds as Bridging Reagents

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An Approach to One‐Pot Regioselective Synthesis of Indenones through Palladium‐Catalyzed Annulation in Water

Cited by 25 publications

References 68 publications

Antiaromatic Dicyclopenta[b,g]/[a,f]naphthalene Isomers Showing an Open-Shell Singlet Ground State with Tunable Diradical Character

Antiaromatic Dicyclopenta[b,g]/[a,f]naphthalene Isomers Showing an Open-Shell Singlet Ground State with Tunable Diradical Character

AlBr3-Promoted stereoselective anti-hydroarylation of the acetylene bond in 3-arylpropynenitriles by electron-rich arenes: synthesis of 3,3-diarylpropenenitriles

Recent Advances in Palladium-Catalyzed Bridging C–H Activation by Using Alkenes, Alkynes or Diazo Compounds as Bridging Reagents

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AlBr₃-Promoted stereoselective anti-hydroarylation of the acetylene bond in 3-arylpropynenitriles by electron-rich arenes: synthesis of 3,3-diarylpropenenitriles