Iodine‐Mediated Cyclization of <i>ortho</i>‐Alkynylaryl Ketones for the Synthesis of Indenone Derivatives

Chuangsoongnern, Pennapa; Surinrach, Chareef; Tummatorn, Jumreang; Thongsornkleeb, Charnsak; Ruchirawat, Somsak

doi:10.1002/ejoc.201700968

Cited by 18 publications

(15 citation statements)

References 42 publications

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“…During their studies in oxidative functionalization reactions of ortho ‐alkynylaryl ketones ( 116 ), Ruchirawat and co‐workers found an unexpected results that molecular iodine promotes a cyclization process by the assistance of a neighboring ketone group, affording indenone products 117 (Scheme 43). [68] The optimal condition was obtained using 1.0 equiv. of both I 2 and H 2 O in dry CH 3 CN at 60 °C for 6 h to furnish the desired product in 73% yield.…”

Section: Carbonyl Participation In Hydrative Carbocylization Reactionsmentioning

confidence: 99%

“…In the mechanism of these reactions, two main reaction sequences are involved: (i) Carbonyl group‐assisted hydration reactions with alkyne followed by aldol‐carbocylization to yield the corresponding indenones 119 [68] . (ii) Next, another intramolecular aldol condensation of tethered 1,3‐dicarbonyl by the nucleophilic attack of enol intermediate 119A or enamine 119B at the indenone‐carbonyl followed by a sequence of dehydration and aromatization furnishes the desired products (Scheme 44C).…”

Section: Carbonyl Participation In Hydrative Carbocylization Reactionsmentioning

confidence: 99%

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An Overview of Water‐Mediated Alkyne Functionalization by Neighboring Group Participation of Carbonyl Groups

Pradhan

Park

2020

Adv Synth Catal

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Reviewed herein, the progress employing the assistance of a neighboring carbonyl group for alkyne functionalization reactions that are mediated by water. Proper arrangement of these transformations is synthetically worthwhile because it will allow chemists to design straightforward synthetic routes for the construction of complex architectures with perfect regio-and chemoselectivity. Researchers must understand the mechanism before aiming a new idea based on these types of transformations as they proceed through a different way in comparison to the strategies that employ carbonyl groups as a directing group for CÀ H functionalization reactions. In general, an oxygen transposition event occurs in the presence of an alkyne activator. In an aim to expose the molecular diversity that can now be accessed employing intramolecular carbonyl assistance, all the precedents are organized systematically for the first time and can be expected to serve as a comprehensive reference work. Therefore, the key arrangement of this review is schemes accompanied by a concise explanatory text describing both advantages and limitations along with the mechanism. Different transformations are ordered in sections according to the chemical structure of the assisted groups. The overall objective of this review is to promote the application of carbonyl-assisted reactions beyond the methodologies dedicated to the regioselective synthesis of carbonyl derivatives and hence, serving it as a valuable reaction archetype in modern-day research for the synthesis of carbo-and heterocycles.

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Section: Carbonyl Participation In Hydrative Carbocylization Reactionsmentioning

confidence: 99%

Section: Carbonyl Participation In Hydrative Carbocylization Reactionsmentioning

confidence: 99%

An Overview of Water‐Mediated Alkyne Functionalization by Neighboring Group Participation of Carbonyl Groups

Pradhan

Park

2020

Adv Synth Catal

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“…[7] In addition, ortho-alkynylarylketones could also be used for preparation of indenone (4) by reacting with molecular iodine (Scheme 1). [8] Spirocyclic ether scaffold is one of the most important pharmacophores present in bioactive natural products and synthetic compounds. Figure 1 illustrated examples of bioactive spirocyclic ethers with various activities such as 19hydroxygrindelic acid (antitumor), filifolinol (antiviral), (+)-ophiobolin A (anticancer and antibiotic), and griseofulvin (antifungal).…”

Section: Introductionmentioning

confidence: 99%

Diastereoselective Synthesis of Spirocyclic Ether from ortho‐Carbonylarylacetylenols via Silver‐Catalyzed Cyclization under Acidic Conditions

et al. 2021

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ortho‐Carbonylarylacetylenol, can be utilized for the synthesis of several important core structures. In this work, a method is developed for the diastereoselective synthesis of spirocyclic ethers using a silver catalyst under the presence of acid. This protocol can be applied to a variety of substrates resulting in the corresponding products in 35–97% yields with good diastereoselectivity. The proposed reaction mechanisms and stereoselectivity outcome of the corresponding products are investigated using DFT calculation. This current protocol can be applied to a broad range of substrates which would be useful for the creation of libraries of spirocylic ethers

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“…Indenones represent common motifs of carbocycles with a prime of importance in many structurally complex bioactive compounds or natural products. 1 Several synthetic methods of indenone have been shown to give moderate selectivities and yields using gold catalysis, 2,3 iodine-mediated strategy, 4 and organolithium reagents. 5 Therefore, advancing a catalytically efficient approach has motivated and attracted many synthetic groups by which a metal-catalyzed cyclization was a premier rout being targeted.…”

Section: Introductionmentioning

confidence: 99%

Revealing Mechanism and Origin of Reactivity of Au(I)-Catalyzed Functionalized Indenone Formation of Cyclic and Acyclic Acetals of Alkynylaldehydes

Hussein

Ali²

2020

Preprint

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<p><a>Density functional theory exploited with the (SMD)-B3LYP-D3/def2-TZVP//B3LYP/6-31G(d),LANL2DZ level of theory is presented to offer mechanistic insights and explications of experimentally intriguing observations in the Au(I)-catalyzed cyclization of cyclic and acyclic acetals of alkynylaldehydes that lead to indenone formation. The reactivity of catalytic cycles with and without methoxy migration is computationally defined when alkyne terminus is phenylated in addition to the unreactive cycle when alkyne terminus is not phenylated. The reaction mechanism of indenone formation proceeds first with coordination of Au(I) to alkyne to initiate the reaction with 1,5-H shift as a rate-determining step and the fastest 1,5-H shift is achieved when one phenyl ring carries electron-donating group and the other one is substituted with electron-withdrawing group. The absence of tethered acetal unit considerably outpaces any 1,5-H shift and instead activates 1,5-methoxy migration, giving methoxy-migrated indenone, with the step of 1,2-OMe shift is a rate-limiting step during reaction pathway. Following 1,5-H shift the cyclization and 1,2-H shift are kinetically and thermodynamically feasible, which are followed by elimination to persist the iterative cycle, but the reactivity of both steps is highly affected by the existence of phenyl group on alkyne terminus. The unreactivity of alkyne terminus being not beared a phenyl ring is due to that the cyclization is thermodynamically disfavorable, subsequently deactivating the 1,2-H shift kinetically and thermodynamically. </a></p>

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Iodine‐Mediated Cyclization of ortho‐Alkynylaryl Ketones for the Synthesis of Indenone Derivatives

Cited by 18 publications

References 42 publications

An Overview of Water‐Mediated Alkyne Functionalization by Neighboring Group Participation of Carbonyl Groups

An Overview of Water‐Mediated Alkyne Functionalization by Neighboring Group Participation of Carbonyl Groups

Diastereoselective Synthesis of Spirocyclic Ether from ortho‐Carbonylarylacetylenols via Silver‐Catalyzed Cyclization under Acidic Conditions

Revealing Mechanism and Origin of Reactivity of Au(I)-Catalyzed Functionalized Indenone Formation of Cyclic and Acyclic Acetals of Alkynylaldehydes

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