Energy transfer photocatalysis: exciting modes of reactivity

Chemical Society Reviews, Journal Year: 2024, Volume and Issue: 53(3), P. 1068 - 1089

Published: Jan. 1, 2024

Leveraging light energy to expose the ‘dark’ reactive states describes whole essence of triplet–triplet transfer. This offers an impressive opportunity conduct a multitude diverse reactions and access sought-after molecular motifs.

Language: Английский

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ortho-Selective Dearomative [2π + 2σ] Photocycloadditions of Bicyclic Aza-Arenes

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(22), P. 12324 - 12332

Published: May 26, 2023

Dearomative photocycloadditions are valuable chemical transformations, serving as an efficient platform to create three-dimensional molecular complexity. However, the photolability of original addition product especially within context ortho cycloadditions often causes undesired consecutive rearrangements, rendering these cycloadducts elusive. Herein, we report ortho-selective intermolecular photocycloaddition bicyclic aza-arenes including (iso)quinolines, quinazolines, and quinoxalines by utilizing a strain-release approach. With bicyclo[1.1.0]butanes coupling partners, this dearomative [2π + 2σ] cycloaddition enables straightforward construction C(sp3)-rich bicyclo[2.1.1]hexanes directly connected N-heteroarenes. Photophysical experiments DFT calculations revealed origin selectivity indicate that, in originally proposed energy transfer or direct excitation pathways, chain reaction mechanism is operative depending on conditions.

Language: Английский

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Catalytic Formal [2π+2σ] Cycloaddition of Aldehydes with Bicyclobutanes: Expedient Access to Polysubstituted 2‐Oxabicyclo[2.1.1]hexanes

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(34)

Published: June 12, 2023

Synthesis of bicyclic scaffolds has attracted tremendous attention because they are playing an important role as saturated bioisosteres benzenoids in modern drug discovery. Here, we report a BF3 -catalyzed [2π+2σ] cycloaddition aldehydes with bicyclo[1.1.0]butanes (BCBs) to access polysubstituted 2-oxabicyclo[2.1.1]hexanes. A new kind BCB containing acyl pyrazole group was invented, which not only significantly facilitates the reactions, but can also serve handle for diverse downstream transformations. Furthermore, aryl and vinyl epoxides be utilized substrates undergo BCBs after situ rearrangement aldehydes. We anticipate that our results will promote challenging sp3 -rich frameworks exploration BCB-based chemistry.

Language: Английский

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Photocatalyzed [2σ + 2σ] and [2σ + 2π] Cycloadditions for the Synthesis of Bicyclo[3.1.1]heptanes and 5- or 6-Membered Carbocycles

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(46), P. 25411 - 25421

Published: Nov. 7, 2023

We report the use of photocatalysis for homolytic ring-opening carbonyl cyclopropanes. In contrast to previous studies, our approach does not require a metal cocatalyst or strong reductant. The cyclopropanes can be employed both [2σ + 2σ] and 2π] annulation with either alkenes/alkynes bicyclo[1.1.0]butanes, yielding cyclopent-anes/-enes bicyclo[3.1.1]heptanes (BCHs), respectively. BCHs are promising bioisosteres 1,2,4,5 tetra-substituted aromatic rings. Mechanistic including density functional theory computation trapping experiment DMPO, support 1,3-biradical generated from cyclopropane as key intermediate these transformations.

Language: Английский

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Piperidine Derivatives: Recent Advances in Synthesis and Pharmacological Applications

International Journal of Molecular Sciences, Journal Year: 2023, Volume and Issue: 24(3), P. 2937 - 2937

Published: Feb. 2, 2023

Piperidines are among the most important synthetic fragments for designing drugs and play a significant role in pharmaceutical industry. Their derivatives present more than twenty classes of pharmaceuticals, as well alkaloids. The current review summarizes recent scientific literature on intra- intermolecular reactions leading to formation various piperidine derivatives: substituted piperidines, spiropiperidines, condensed piperidinones. Moreover, applications natural piperidines were covered, latest advances discovery biological evaluation potential containing moiety. This is designed help both novice researchers taking their first steps this field experienced scientists looking suitable substrates synthesis biologically active piperidines.

Language: Английский

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EDA photochemistry: Mechanistic investigations and future opportunities

Chem, Journal Year: 2023, Volume and Issue: 9(9), P. 2390 - 2415

Published: July 18, 2023

Language: Английский

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Silver‐Enabled Cycloaddition of Bicyclobutanes with Isocyanides for the Synthesis of Polysubstituted 3‐Azabicyclo[3.1.1]heptanes

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(21)

Published: March 5, 2024

Abstract Synthesis of bicyclic scaffolds has emerged as an important research topic in modern drug development because they can serve saturated bioisosters to enhance the physicochemical properties and metabolic profiles candidates. Here we report a remarkably simple silver‐enabled strategy access polysubstituted 3‐azabicyclo[3.1.1]heptanes single operation from readily accessible bicyclobutanes (BCBs) isocyanides. The process is proposed involve formal (3+3)/(3+2)/retro‐(3+2) cycloaddition sequence. This novel protocol allows for rapid generation molecular complexity starting materials, products be easily derivatized, further enriching BCB chemistry growing set valuable sp 3 ‐rich building blocks.

Language: Английский

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Copper-Catalyzed Enantioselective [4π + 2σ] Cycloaddition of Bicyclobutanes with Nitrones

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: unknown

Published: Sept. 25, 2024

The selective construction of bridged bicyclic scaffolds has garnered increasing attention because their extensive use as saturated bioisosteres arene in pharmaceutical industry. However, sharp contrast to racemic counterparts, assembling chiral structures an enantioselective and regioselective manner remains challenging. Herein, we describe our protocol for constructing 2-oxa-3-azabicyclo[3.1.1]heptanes (BCHeps) by [4π + 2σ] cycloadditions bicyclo[1.1.0]butanes (BCBs) nitrones taking advantage a copper(II) complex Lewis acid catalyst. This method features mild conditions, good functional group tolerance, high yield (up 99%), excellent enantioselectivity 99% ee). Density theory (DFT) calculation elucidates the origin reaction's mechanism BCB activation Cu(II) complex.

Language: Английский

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Formal Cycloadditions Driven by the Homolytic Opening of Strained, Saturated Ring Systems

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 62(4)

Published: Oct. 14, 2022

Abstract The field of strain‐driven, radical formal cycloadditions is experiencing a surge in activity motivated by renaissance free chemistry and growing demand for sp 3 ‐rich ring systems. former has been driven large part the rise photoredox catalysis, latter adoption “Escape from Flatland” concept medicinal chemistry. In years since these broader trends emerged, dozens cycloadditions, including catalytic, asymmetric variants, have developed that operate via mechanisms. While cyclopropanes studied most extensively, variety strained systems are amenable to design analogous reactions. Many processes generate lucrative, functionally decorated difficult access other means. Herein, we summarize recent efforts this area analyze state field.

Language: Английский

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Asymmetric [3 + 2] Photocycloaddition of β-Keto Esters and Vinyl Azides by Dual Photoredox/Nickel Catalysis

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(22), P. 12233 - 12243

Published: May 24, 2023

Photocatalytic [3 + 2] cycloadditions and control of stereochemistry have remained a substantial challenge, particularly in the context heterocycle synthesis; sporadic successful examples involved enantioselective photocycloaddition between redox-active direct group-containing cyclopropanes alkenes for creation cyclopentanes. Herein, we report cooperative catalytic system comprising chiral nickel Lewis acid catalyst an organic photocatalyst fueled by visible-light irradiation that allows hitherto elusive asymmetric β-keto esters with vinyl azides under redox-neutral conditions. This protocol enables highly construction polycyclic densely substituted 3,4-dihydro-2H-pyrrole heterocycles featuring two contiguous tetrasubstituted carbon stereocenters, including useful N,O-ketal motif is not easily accessible other methods. Mechanistic studies revealed overall reactivity relies on seamless integration dual roles catalysts formation substrate/Ni complex, assisting both photoredox event radical addition.

Language: Английский

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