Zinc‐Chloride‐Promoted Domino Reaction of Phenols with Terminal Alkynes under Solvent‐Free Conditions: An Efficient Synthesis of Chromenes

Sreenivasulu, Chinnabattigalla; Satyanarayana, Gedu

doi:10.1002/ejoc.201800391

Cited by 17 publications

(5 citation statements)

References 64 publications

(19 reference statements)

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“…However, a new 1-substituted pyrene-based system containing olefinic bonds (CC) ( 6b ) was synthesized in 39% yield via a ZnCl 2 -catalyzed one-step reaction. We infer that the relatively low electron-donating ability of the methoxyl group cannot further trigger the cyclization reaction to form a stable pyrene-based chromene compound ( 6a ) . All target compounds demonstrated good solubility in common organic solvents (such as CH 2 Cl 2 , THF, and DMSO), which is beneficial for further characterization of their molecular structures and purity.…”

Section: Resultsmentioning

confidence: 99%

Pyrene-Based Deep-Blue Fluorophores with Narrow-Band Emission

Liu,

Zhang,

Wang

et al. 2024

J. Org. Chem.

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High-efficiency narrow-band luminescent materials have attracted intense interest, resulting in their great colorimetric purity. This has led to a variety of high-tech applications in highdefinition displays, spectral analysis, and biomedicine. In this study, a rigid pyrene core was employed as the molecular backbone, and four narrow-band pyrene-based blue emitters were synthesized using various synthetic methods (such as Lewis-acid catalyzed cyclization domino reactions, Pd-catalyzed coupling reactions like Suzuki− Miyaura and Sonogashira). Due to the steric effect of the hydroxy group at the 2-position, the target compounds exhibit deep blue emission (<429 nm, CIEy < 0.08) with full width at half-maximum (FWHM) less than 33 nm both in solution and when solidified. The experimental and theoretical results indicated that the substituents at the 1-and 3-positions afford a large dihedral angle with the pyrene core, and the molecular motion is almost fixed by multiple intra-and intermolecular hydrogen bonding interactions in the crystallized state, leading to a suppression of the vibrational relaxation of the molecular structure. Moreover, we observed that the suppression of the vibrational relaxation in the molecular structures and the construction of rigid conjugated structures can help develop narrow-band organic light-emitting materials.

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Section: Resultsmentioning

confidence: 99%

Pyrene-Based Deep-Blue Fluorophores with Narrow-Band Emission

Liu,

Zhang,

Wang

et al. 2024

J. Org. Chem.

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“…[ 156–158 ] Interestingly, good enantioselectivity and excellent yields have been attained by this strategy. The reaction proceeds via ortho‐ C–H bond activation of the aromatic ketones 54 by the cationic iridium complex, in which it was presumed that 2 H ‐chromenes 55 [ 159 ] are converted into 4 H ‐chromenes 57 . [ 160 ] The best results were obtained when using catalytic amount of [Ir(cod)Cl] 2 (5 mol%), ( R )‐DM‐Segphos (6 mol%), 10 mol% of NaBAr F 4 along with 2 H ‐chromenes 55 and aromatic ketones 54 (1:1.2 equiv) at 80°C for 48 h in toluene.…”

Section: Resultsmentioning

confidence: 99%

Recent advances on the synthesis of flavans, isoflavans, and neoflavans

Sreenivasulu

Dakoju

Satyanarayana

2020

Journal of Heterocyclic Chem

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Heterocyclic compounds are the omnipresent structural cores comprising many natural and pharmaceutical products of biological significance. Significantly, heterocyclic compounds are widely distributed in nature, and also have applications in agrochemicals, sanitizers, as dyestuff, as copolymers, etc. Among heterocyles, flavonoids are a class of compounds that are highly interesting and constitute many natural products. In general, all flavanoids contains a basic core of C6‐C3‐C6 of phenyl‐benzopyran backbone. The relative placement of the phenyl group on to the benzopyran core makes further classification into flavanoids, isoflavanoids and neoflavanoids. Flavans (2‐aryl chroman) are subclass of anthoxanthanes exhibits a broad spectrum of biological properties such as anti‐inflammatory, anti‐oxidant, and anti‐malarial properties. Some representative naturally occurring products possessing flavan core are apigenin, luteolin, tangeretin, scutellarein, etc. On the other hand, some of the notable isoflavan‐based natural products are glabridin and (S)‐(−)‐equol. Glabridin is isolated from Licorice roots, which regulates paraoxonase (PON2) levels. While the simple isoflavan (S)‐(−)‐equol, is produced from soy isoflavone intake. Also, natural products such as dalbergichromene, centchroman, and (+)‐myristinin A possess neoflavan (4‐aryl‐3,4‐dihydro‐2H‐chromenes) core structure. Owing to their broad biological and pharmacological properties, synthetic chemists are fascinated in developing new routes toward their synthesis. As a result, a decent number of reports have been established in the literature. Thus, for the past 5 years of time frame, many new methodologies have been witnessed, for the synthesis of various flavan systems. This review emphasizes most of the significant methods on accomplishing flavans, isoflavans and neoflavans and also focused on their applications to the synthesis of relevant natural as well as biologically active products.

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“…However, these methods require metal catalysis or are limited to aryl propargylic alcohols or 3-alkoxy propargylic alcohols. In view of these limitations for substitutions on the propargylic alcohol substrates and as a continuation of our research experience on alkyne chemistry, − here we sought to develop a simple and efficient method for the synthesis of α-iodoenones using N -iodosuccinimide, a reagent supplying an iodine atom (iodo-source). Notably, this method is also appropriate for the large-scale synthesis of α-iodoenone derivatives.…”

Section: Introductionmentioning

confidence: 99%

“…Our group has been uninterruptedly engaged in transition metal-catalyzed coupling reactions with alkynes ,,,, and alkenes − as the coupling partners to synthesize various carbo- and heterocyclic products. In continuation, herein we demonstrated a novel alkyl or Bn 3-(2-oxo-6-aryl-5-(prop-1-en-2-yl)-2 H -pyran-3-yl)propanoate from α-iodoenone derivatives via the Heck coupling and base-mediated Michael addition of acrylates, followed by cyclo-condensation through double-bond isomerization (Figure f).…”

Section: Introductionmentioning

confidence: 99%

A Metal-Free Path to 2-Iodo-3-alkyl-1-arylbut-2-en-1-ones and Their Application to the Domino Synthesis of Functionalized 2H-Pyran-2-ones

Sreenivasulu

Satyanarayana

2022

J. Org. Chem.

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We report a metal-free selective synthesis of 2-iodo-3-alkyl-1-arylbut-2-en-1-ones from propargylic alcohols that is enabled by N-iodosuccinimide. A variety of substituted propargylic alcohols are amenable to delivering the selective 2-iodoenone products in very good yields. The utility of the α-iodoenone derivatives is further extended by developing an efficient, novel, and new synthetic methodology for the synthesis of 3,5,6trisubstituted 2H-pyran-2-ones. To the best of our knowledge, this protocol is the first of its kind to accomplish 3,5,6trisubstituted 2H-pyran-2-ones through an unprecedented domino (formation of two C−C bonds and one C−O bond) one-pot process via intermolecular Heck coupling, base-driven Michael addition, and base-mediated double bond isomerization followed by cyclo-condensation. This protocol showed good compatibility with a wide range of iodoenones (18 examples) and 2H-pyran-2-ones (42 examples). Mechanistic studies indicate that palladium is only involved in the Heck coupling; the base solely drives the rest of the steps.

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Zinc‐Chloride‐Promoted Domino Reaction of Phenols with Terminal Alkynes under Solvent‐Free Conditions: An Efficient Synthesis of Chromenes

Cited by 17 publications

References 64 publications

Pyrene-Based Deep-Blue Fluorophores with Narrow-Band Emission

Pyrene-Based Deep-Blue Fluorophores with Narrow-Band Emission

Recent advances on the synthesis of flavans, isoflavans, and neoflavans

A Metal-Free Path to 2-Iodo-3-alkyl-1-arylbut-2-en-1-ones and Their Application to the Domino Synthesis of Functionalized 2H-Pyran-2-ones

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