Cr(II)-promoted internal cyclization of acyclic enediynes fused to benzo[b]thiophene core: Macrocycles versus 2-methylenecycloalkan-1-ols formation

Kulyashova, Alexandra E.; Пономарев, А. В.; Селиванов, С. И.; Khlebnikov, Alexander F.; Popik, Vladimir V.; Балова, Ирина А.

doi:10.1016/j.arabjc.2018.05.005

Cited by 4 publications

(3 citation statements)

References 96 publications

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“…Cyclooctynes BT8O and IC8O possess RSE values higher than 3,4-MOBO for 2 and 1 kcal/mol, respectively. This trend coincides with the known fact of the increased RSE for structures with five-membered annulated rings compared to six-membered. ,− However, BT8S (14.6 kcal/mol) and BT9O (13.6 kcal/mol) possess significantly lower RSE values than 3,4-MOBO and similar RSE values to other known stable SPAAC reagents ( DIFO, COMBO, F ) (Figure ). Thus, RSE is not the only reason for the instability of all the target cyclooctynes and BT9O .…”

Section: Resuts and Discussionsupporting

confidence: 84%

Heterocycloalkynes Fused to a Heterocyclic Core: Searching for an Island with Optimal Stability-Reactivity Balance

et al. 2021

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In the search for fundamentally new, active, stable, and readily synthetically accessible cycloalkynes as strain-promoted azide–alkyne cycloaddition (SPAAC) reagents for bioorthogonal bioconjugation, we integrated two common approaches: the reagent destabilization by the increase of a ring strain and the transition state stabilization through electronic effects. As a result new SPAAC reagents, heterocyclononynes fused to a heterocyclic core, were created. These compounds can be obtained through a general synthetic route based on four crucial steps: the electrophile-promoted cyclization, Sonogashira coupling, Nicholas reaction, and final deprotection of Co-complexes of cycloalkynes from cobalt. Varying the natures of the heterocycle and heteroatom allows for reaching the optimal stability-reactivity balance for new strained systems. Computational and experimental studies revealed similar SPAAC reactivities for stable 9-membered isocoumarin- and benzothiophene-fused heterocycloalkynes and their unstable 8-membered homologues. We discovered that close reactivity is a result of the interplay of two electronic effects, which stabilize SPAAC transition states (πin* → σ* and π* → πin*) with structural effects such as conformational changes from eclipsed to staggered conformations in the cycloalkyne scaffold, that noticeably impact alkyne bending and reactivity. The concerted influence of a heterocycle and a heteroatom on the polarization of a triple bond in highly strained cycles along with a low HOMO–LUMO gap was assumed to be the reason for the unpredictable kinetic instability of all the cyclooctynes and the benzothiophene-fused oxacyclononyne. The applicability of stable isocoumarin-fused azacyclononyne IC9N-BDP-FL for in vitro bioconjugation was exemplified by labeling and visualization of HEK293 cells carrying azido-DNA and azido-glycans.

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Section: Resuts and Discussionsupporting

confidence: 84%

Heterocycloalkynes Fused to a Heterocyclic Core: Searching for an Island with Optimal Stability-Reactivity Balance

et al. 2021

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“…One could hypothesize that these macrocyclization techniques could be unsuitable for such highly strained 10-membered benzothiophene enediynes. [45][46][47] Next, DSC measurements for the evaluation of activation parameters of enediyne 1 in the Bergman cyclization were performed. 58 Activation energy value derived from the Arrhenius plot was found to be 28.2 ± 0.5 kcal/mol, 59 that is higher than E a values for oxaenediyne 2 (25.1 ± 0.6 kcal/mol) and carboenediyne 3 (27.0 ± 1.0 kcal/mol) obtained by the same method.…”

Section: Letter Syn Lettmentioning

confidence: 99%

“…Recently we have discovered that the Nicholas-type macrocyclization is a good synthetic tool for the construction of 10-membered oxa-and carbocyclic enediynes fused to a benzothiophene (Scheme 1, C), 43,44 whereas another macrocyclization technique based on the Nozaki reaction 45 and ring-closing metathesis (RCM) 46,47 can be used only for larger cycles because of increased strain that came from the benzothiophene fusion. We have also confirmed, that an-N. A. Danilkina et al…”

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confidence: 99%

10-Membered Azaenediyne Fused to a Benzothiophene through the Nicholas Macrocyclization: Synthesis and DNA Cleavage Ability

Danilkina¹,

Rumyantsev²,

Lyapunova³

et al. 2018

Synlett

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The Nicholas-type macrocyclization through NH-tosyl functional group has been found to be an efficient technique for the synthesis of a 10-membered azaenediyne system annulated with a benzothiophene. To compare the activity of azaenediyne synthesized with similar oxa- and carbocyclic enediynes the Bergman cyclization activation energies and the ability of enediynes to cleave DNA (pBR322 plasmid) were investigated. The order of reactivity predicted by DFT calculations (N-enediyne < C-enediyne < O-enediyne) was confirmed by DSC analysis data. Surprisingly azaenediyne was found to be more active in the DNA cleavage assay than the C-analogue.

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Divalent chromium in the octahedral positions of the novel hybrid perovskites CH3NH3Pb1-Cr (Br,Cl)3 (x = 0.25, 0.5): Induction of narrow bands inside the bandgap

Serrano‐Sánchez

Conesa

Rodrigues

et al. 2020

Journal of Alloys and Compounds

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Cr(II)-promoted internal cyclization of acyclic enediynes fused to benzo[b]thiophene core: Macrocycles versus 2-methylenecycloalkan-1-ols formation

Cited by 4 publications

References 96 publications

Heterocycloalkynes Fused to a Heterocyclic Core: Searching for an Island with Optimal Stability-Reactivity Balance

Heterocycloalkynes Fused to a Heterocyclic Core: Searching for an Island with Optimal Stability-Reactivity Balance

10-Membered Azaenediyne Fused to a Benzothiophene through the Nicholas Macrocyclization: Synthesis and DNA Cleavage Ability

Divalent chromium in the octahedral positions of the novel hybrid perovskites CH3NH3Pb1-Cr (Br,Cl)3 (x = 0.25, 0.5): Induction of narrow bands inside the bandgap

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