Uncovering the Neglected Similarities of Arynes and Donor–Acceptor Cyclopropanes

Angewandte Chemie International Edition, Год журнала: 2019, Номер 59(9), С. 3385 - 3398

Опубликована: Сен. 17, 2019

Arynes and donor-acceptor (D-A) cyclopropanes are two classes of strained systems having the potential for numerous applications in organic synthesis. The last decades have witnessed a renaissance interest chemistry these species primarily because mild robust methods their generation or activation. Commonly, arynes as easily polarizable result 1,2-disubstitution, whereas D-A polarized lead to 1,3-bisfunctionalization thereby showing striking similarities. Transformations with 1,2- 1,3-dipoles afford cyclic structures. With arynes, emerging four-membered rings intermediates might react further, analogous five-membered obtained from most often final products. However, there few cases where behave surprisingly differently. This Minireview highlights parallels reactivity between shedding light on neglected similarities reactive species.

Язык: Английский

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Exploiting Heavier Organochalcogen Compounds in Donor–Acceptor Cyclopropane Chemistry

Accounts of Chemical Research, Год журнала: 2021, Номер 54(6), С. 1528 - 1541

Опубликована: Март 4, 2021

ConspectusDonor–acceptor (D–A) cyclopropanes have gained increased momentum over the past two decades. The use of these highly strained three-membered entities paved way to innovative and original transformations yielding complex cyclic acyclic architectures that otherwise might be difficult address. Since fundamentals were laid by Wenkert Reissig in late 1970s, field has flourished impressively including asymmetric as well elegant synthetic applications construction natural occurring products. In this Account, we aim highlight especially our efforts context an efficient access sulfur- selenium-containing compounds, either or open-chain nature, exploiting D–A cyclopropane chemistry. Light will shed on three fundamental transformations: ring-opening reactions, cycloadditions, rearrangements.Our endeavors started back 2011 guided quantum chemical studies obtain 3,3′-linked bisthiophenes along with unprecedented rearrangement delivering cagelike scaffolds. Inspired surprising results, further deepened new sulfur–carbon selenium–carbon bonds within first instance, capitalized great versatility organosulfur organoselenium compounds regarding their amphiphilic character act nucleophilic electrophilic species. By such approach, ring-openings via a attack sulfenyl selenyl halides furnished 1,3-bishalochalcogenated A similar protocol led us desymmetrization reaction meso-cyclopropyl carbaldehydes employing novel chiral imidazolidinone organocatalysts. contrast, sulfur was supplied N-(arylthio)succinimide substrates thiolated γ-amino acid derivatives selenium equivalents.Combining reactive thiocarbonyl vicinal donor–acceptor substituted opened vistas atom-economic cycloaddition reactions build up sulfur-containing heterocycles various sizes. systematic study made group 2017 leading decorated thiolanes, whereas intramolecular approach thia-[n.2.1]bicyclic ring systems. Our investigations then successfully extended synthesis tetrahydroselenophenes using capricious selenoketones. Recently, able yield unsaturated analogues, selenophenes, (3 + 2)-cycloaddition ammonium selenocyanates followed oxidation. formal insertion thioketenes realized 3-thioxocyclobutanones surrogates for disubstituted 2-substituted tetrahydrothiophenes bearing semicyclic double bond 2) spiroannulation/(2 cycloreversion sequence. Even formation seven-membered S-heterocycles (4 3)-cycloaddition processes. 2016, demonstrated benzo-fused dithiepines from situ generated ortho-bisthioquinones, utilization thia-Michael systems hetero-4π-component delivered tetrahydrothiepine containing just one atom embedded system.

Язык: Английский

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Selective [2σ + 2σ] Cycloaddition Enabled by Boronyl Radical Catalysis: Synthesis of Highly Substituted Bicyclo[3.1.1]heptanes

Journal of the American Chemical Society, Год журнала: 2023, Номер 145(7), С. 4304 - 4310

Опубликована: Фев. 10, 2023

In contrast to the traditional and widely-used cycloaddition reactions involving at least a π bond component, [2σ + 2σ] radical between bicyclo[1.1.0]butanes (BCBs) cyclopropyl ketones has been developed provide modular, concise, atom-economical synthetic route substituted bicyclo[3.1.1]heptane (BCH) derivatives that are 3D bioisosteres of benzenes core skeleton number terpene natural products. The reaction was catalyzed by combination simple tetraalkoxydiboron(4) compound B2pin2 3-pentyl isonicotinate. broad substrate scope demonstrated synthesizing series new highly functionalized BCHs with up six substituents on 99% isolated yield. Computational mechanistic investigations supported pyridine-assisted boronyl catalytic cycle.

Язык: Английский

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Palladium-Catalyzed Ligand-Controlled Switchable Hetero-(5 + 3)/Enantioselective [2σ+2σ] Cycloadditions of Bicyclobutanes with Vinyl Oxiranes

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(29), С. 19621 - 19628

Опубликована: Май 13, 2024

For nearly 60 years, significant research efforts have been focused on developing strategies for the cycloaddition of bicyclobutanes (BCBs). However, higher-order and catalytic asymmetric BCBs long-standing formidable challenges. Here, we report Pd-catalyzed ligand-controlled, tunable cycloadditions divergent synthesis bridged bicyclic frameworks. The dppb ligand facilitates formal (5+3) vinyl oxiranes, yielding valuable eight-membered ethers with scaffolds in 100% regioselectivity. Cy-DPEphos promotes selective hetero-[2σ+2σ] to access pharmacologically important 2-oxabicyclo[3.1.1]heptane (O-BCHeps). Furthermore, corresponding O-BCHeps 94–99% ee has achieved using chiral (S)-DTBM-Segphos, representing first cross-dimerization two strained rings. obtained are promising bioisosteres ortho-substituted benzenes.

Язык: Английский

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Donor–Acceptor Cyclopropanes as an Expedient Building Block Towards the Construction of Nitrogen‐Containing Molecules: An Update

Advanced Synthesis & Catalysis, Год журнала: 2019, Номер 362(7), С. 1447 - 1484

Опубликована: Дек. 19, 2019

Abstract Nitrogen‐containing molecules are the key structural constituent of many pharmaceutical compounds that play a pivotal role in drug development. Owing to their multifaceted medicinal importance, several synthetic approaches have been delineated recent past for construction. Over few decades augmented use donor–acceptor cyclopropanes (DACs) as three‐carbon equivalents, despite ring strain, construction innumerable hetero‐ and carbocycles importance has raised interest chemists this topic. zwitterionic nature due vicinal disposition donor acceptor groups, they frequently used ring‐opening reactions, cycloadditions, rearrangements. This review is mainly focused on assorted reactions DACs with various nitrogen‐containing dipolarophiles like imines, azides, cyanates, isothiocyanates, nitrosocarbonyls, hydrazines, diaziridines, triazinanes, diazenes, etc. towards synthesis industrial importance. continuation our published Israel Journal Chemistry April 2016, includes literature from 2016 May 2019. magnified image

Язык: Английский

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Progress in the chemistry of nitrogen-, oxygen- and sulfur-containing heterocyclic systems

Russian Chemical Reviews, Год журнала: 2019, Номер 89(1), С. 55 - 124

Опубликована: Сен. 27, 2019

The review is devoted to modern trends in the chemistry of nitrogen-, oxygen-and sulfur-containing monocyclic, polynuclear and benzo(hetero)annulated heterocyclic compounds. Methods for synthesis chemical reactivity furazan, furoxan, thiazole, thiadiazole, dithiazole, thiophene, glycoluril, imidazotriazine, diaziridine other heterocycles are discussed. Characteristic features reactions depending on structure starting compounds, intermediates reaction medium (organic solvents, ionic liquids) mechanistic aspects most interesting transformations considered. Data biological activities prospects practical applications indicated systems presented. bibliography includes 383 references.

Язык: Английский

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Kinetic Studies of Donor–Acceptor Cyclopropanes: The Influence of Structural and Electronic Properties on the Reactivity

Angewandte Chemie International Edition, Год журнала: 2018, Номер 58(7), С. 1955 - 1959

Опубликована: Дек. 18, 2018

The kinetics of (3+2) cycloaddition reactions 18 different donor-acceptor cyclopropanes with the same aldehyde were studied by in situ NMR spectroscopy. Increasing electron density donor residue accelerates reaction a factor up to 50 compared standard system (donor group=phenyl), whereas electron-withdrawing substituents slow down 660. This behavior is agreement Hammett substituent parameter σ. obtained rate constants from cycloadditions correlate well data additionally (3+n) nitrone (n=3) and an isobenzofuran (n=4). A comparison kinetic bond lengths cyclopropane (obtained X-ray diffraction computation), or 1 H 13 C shifts, revealed no correlation. However, computed relaxed force proved be good indicator for reactivity three-membered ring.

Язык: Английский

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(3+3)‐Annulation of Carbonyl Ylides with Donor–Acceptor Cyclopropanes: Synergistic Dirhodium(II) and Lewis Acid Catalysis

Angewandte Chemie International Edition, Год журнала: 2019, Номер 58(19), С. 6225 - 6229

Опубликована: Фев. 13, 2019

The first (3+3)-annulation process of donor-acceptor cyclopropanes using synergistic catalysis is reported. Rh2 (OAc)4 -catalyzed decomposition diazo carbonyl compounds generated ylides in situ. These 1,3-dipoles were converted with cyclopropanes, activated by Lewis acid catalysis, to afford multiply substituted pyran scaffolds high yield and diastereoselectivity. Extensive optimization studies enabled access 9-oxabicyclo[3.3.1]nonan-2-one 10-oxabicyclo[4.3.1]decen-2-ol cores, exploiting solvent effects on intermediate reactivity.

Язык: Английский

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Electrocatalytic Activation of Donor–Acceptor Cyclopropanes and Cyclobutanes: An Alternative C(sp³)−C(sp³) Cleavage Mode

Angewandte Chemie International Edition, Год журнала: 2021, Номер 60(29), С. 15928 - 15934

Опубликована: Апрель 23, 2021

We describe the first electrochemical activation of D-A cyclopropanes and cyclobutanes leading after C(sp

Язык: Английский

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(4 + 3)-Cycloaddition of Donor–Acceptor Cyclopropanes with Thiochalcones: A Diastereoselective Access to Tetrahydrothiepines

Organic Letters, Год журнала: 2019, Номер 21(23), С. 9405 - 9409

Опубликована: Ноя. 11, 2019

A general approach is described for the formation of tetrahydrothiepines using donor-acceptor cyclopropanes. Thiochalcones, functioning as sulfur-containing four-atom building blocks, were reacted in a Lewis acid catalyzed formal (4 + 3)-cycloaddition reaction with cyclopropanes three-atom blocks. Under mild conditions various synthesized good yields stereospecific high functional group tolerance.

Язык: Английский

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