Diastereoselective Transfer of Tri(di)fluoroacetylsilanes‐Derived Carbenes to Alkenes

Angewandte Chemie International Edition, Год журнала: 2022, Номер 61(25)

Опубликована: Апрель 13, 2022

Stereoselective cyclopropanation reaction of alkenes is usually achieved by metal complexes via singlet-metal-carbene intermediates. However, previous transition-metal-catalyzed with acylsilanes afforded low diastereoselectivity. Herein, we report the first visible-light-induced transition-metal-free terminal trifluoroacetylsilanes and difluoroacetylsilanes. Both aromatic aliphatic as well electron-deficient are suitable substrates for highly cis-selective [2+1] cyclization reaction. A combination experimental computational studies identified triplet carbenes being key intermediates in this transformation. The gram scale late-stage functionalization demonstrated synthetic potential strategy.

Язык: Английский

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Electron‐Rich Oxycarbenes: New Synthetic and Catalytic Applications beyond Group 6 Fischer Carbene Complexes

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(13)

Опубликована: Янв. 3, 2023

Abstract Oxycarbenes have emerged as useful intermediates in synthetic chemistry. Compared to the widely studied oxycarbene metal complexes bearing Group 6 metals, and catalytic applications of oxycarbenes beyond Fischer carbene are less explored because difficulty controlling their reactivity need use a stoichiometric amount presynthesized complex starting material. This Minireview summarizes early late‐transition‐metal highlights recent advances free reactions transition‐metal‐catalyzed involving oxycarbenes. We hope this will inspire further developments emerging area.

Язык: Английский

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Catalytic synthesis of β-lactam derivatives by carbonylative cycloaddition of acylsilanes with imines via a palladium Fischer-carbene intermediate

Nature Catalysis, Год журнала: 2024, Номер 7(2), С. 132 - 138

Опубликована: Янв. 15, 2024

Abstract Fischer-type carbene complexes are characterized by the presence of a π -donating group, such as an alkoxy group on carbon. Despite notable progress that has been made in synthetic methods involve use complexes, stoichiometric amounts still required for reactions and catalytic variants remain elusive. This limitation primarily stems from lack suitable precursors, which is sharp contrast to fact bearing electron-withdrawing can be readily generated corresponding diazo esters. Here we report acylsilanes function precursor Fischer-carbene complex action palladium catalyst. system used carbonylative cycloaddition with imines form densely substituted β-lactam derivatives. A key siloxycarbene–palladium intermediate was isolated successfully X-ray crystallography.

Язык: Английский

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Radical Brook rearrangement: past, present, and future

Chemical Society Reviews, Год журнала: 2025, Номер unknown

Опубликована: Янв. 1, 2025

This review aims to provide an overview of radical Brook rearrangement, which is organized by grouping three type reactive species generated via the unique rearrangement process.

Язык: Английский

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Intramolecular photochemical [2 + 1]-cycloadditions of nucleophilic siloxy carbenes

Chemical Science, Год журнала: 2022, Номер 13(11), С. 3273 - 3280

Опубликована: Янв. 1, 2022

Visible light induced singlet nucleophilic carbenes undergo rapid [2 + 1]-cycloaddition with tethered olefins to afford unique bicyclo[3.1.0]hexane and bicyclo[4.1.0]heptane scaffolds. This cyclopropanation process requires only visible irradiation proceed, circumventing the use of exogenous (photo)catalysts, sensitisers or additives showcases a vastly underexplored mode reactivity for in chemical synthesis. The discovery additional transformations including cyclopropanation/retro-Michael/Michael cascade chromanones photochemical C-H insertion reaction are also described.

Язык: Английский

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Visible Light‐Mediated Cyclopropanation: Recent Progress

European Journal of Organic Chemistry, Год журнала: 2022, Номер 2022(44)

Опубликована: Окт. 21, 2022

Abstract Cyclopropanes are one of the most important strained rings existing in various pharmaceutical products and secondary metabolites. They also widely used total synthesis natural products, medicinal chemistry, materials science. In past years, photochemical cyclopropanation has been gradually developed as a robust attractive synthetic method to prepare diverse cyclopropane backbones. this review, we summarize recent advances visible light‐mediated synthesis, especially using carbene transfer strategy photocatalytic radical reactions.

Язык: Английский

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Recent progress and perspectives in photo-induced organic reactions of acylsilanes

Organic Chemistry Frontiers, Год журнала: 2023, Номер 10(3), С. 819 - 836

Опубликована: Янв. 1, 2023

This review provides recent advances and insights into photoirradiation reactions of acylsilanes, notably via key nucleophilic siloxycarbene intermediates. Nucleophilic addition, insertion reaction, cyclization are discussed in terms reaction mechanism scope.

Язык: Английский

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Visible-Light-Mediated Energy Transfer Enables Cyclopropanes Bearing Contiguous All-Carbon Quaternary Centers

ACS Catalysis, Год журнала: 2023, Номер 13(14), С. 9806 - 9816

Опубликована: Июль 11, 2023

Cyclopropanes bearing contiguous all-carbon quaternary centers continue to attract attention due their bioactivities. However, methods obtain cyclopropanes with remain largely unexplored the high steric hindrance of these compounds. Herein, we report a visible-light-mediated energy-transfer (EnT) strategy realize in situ donor/donor carbenes from readily available N-tosylhydrazones, facilitating synthesis highly congested EWG-free cyclopropanes. Through this approach, are rapidly installed into complex bioactive molecules, fluorescent and other useful building blocks that challenging synthesize. Detailed mechanistic reactions DFT studies clearly demonstrated role photosensitizer, formation carbenes, necessity light base system.

Язык: Английский

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Photosensitized O ₂ enables intermolecular alkene cyclopropanation by active methylene compounds

Science, Год журнала: 2023, Номер 381(6657), С. 545 - 553

Опубликована: Авг. 3, 2023

Cyclopropanes are key features in many preclinical, clinical, and commercial drugs, as well natural products. The most prolific technique for their synthesis is the metal-catalyzed reaction of an alkene with a diazoalkane, highly energetic reagent requiring stringent safety precautions. Discovery alternative innocuous reagents remains ongoing challenge. Herein, we report simple photoredox-catalyzed intermolecular cyclopropanation unactivated alkenes active methylene compounds. proceeds neutral solvent under air or dioxygen (O 2 ) photoredox catalyst excited by blue light-emitting diode light iodine co-catalyst that either added molecular generated situ from alkyl iodides. Mechanistic investigations indicate photosensitized O plays vital role generation carbon-centered radicals both addition compounds to ring closure.

Язык: Английский

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Photocatalyzed Borylcyclopropanation of Alkenes with a (Diborylmethyl)iodide Reagent

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(38)

Опубликована: Авг. 2, 2023

Cyclopropane skeletons play a prominent role in the development of organic synthesis and pharmaceutical chemistry. Herein, we report design stable, multifunctional (diborylmethyl)iodide reagent (CHI(Bpin)2 ) for photoinduced cyclopropanation alkenes, providing an array 1,2-substituted cyclopropylboronates good yields. This α-haloboronic ester can be readily synthesized on multigram scale from commercially available starting materials. Furthermore, protocol displays high chemo- diastereoselectivity, excellent functional-group tolerance, allows late-stage borylcyclopropanation complex molecules. Mechanistic studies reveal that proceeds through radical addition/polar cyclization pathway mediated by photocatalyst fac-Ir(ppy)3 visible light.

Язык: Английский

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