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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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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Enantioselective [2π + 2σ] Cycloadditions of Bicyclo[1.1.0]butanes with Vinylazaarenes through Asymmetric Photoredox Catalysis

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(12), P. 8372 - 8380

Published: March 18, 2024

Here we present a highly enantioselective [2π + 2σ] photocycloaddition of bicyclo[1.1.0]butanes (BCBs). The reaction uses variety vinylazaarenes as partners and is catalyzed by polycyclic aromatic hydrocarbon (PAH)-containing chiral phosphoric acid bifunctional photosensitizer. A wide array pharmaceutically important bicyclo[2.1.1]hexane (BCH) derivatives have been synthesized with high yields, enantioselectivity, diastereoselectivity. In addition to the diverse 1-ketocarbonyl-3-substituted BCBs, α/β-substituted are compatible such an unprecedented photoredox catalytic pathway, resulting in successful assembly all-carbon quaternary stereocenter or two adjacent tertiary stereocenters on product.

Language: Английский

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Photoredox-Enabled Dearomative [2π + 2σ] Cycloaddition of Phenols

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(4), P. 2789 - 2797

Published: Jan. 18, 2024

Dearomative photocycloaddition of monocyclic arenes is an appealing strategy for comprehending the concept "escape from flatland". This brings replacement readily available planar aromatic hydrocarbon units with a 3D fused bicyclic core sp3-enriched carbon units. Herein, we outline intermolecular approach dearomative phenols. In order to circumvent ground-state aromaticity and construct conformationally restrained building blocks, bicyclo[1.1.0]butanes were chosen as coupling partners. renders straightforward access bicyclo[2.1.1]hexane unit cyclic enone moiety, which further contributed synthetic linchpin postmodifications. Mechanistic experiment advocates plausible onset both reactants, depending on redox potential.

Language: Английский

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Hantzsch Esters Enabled [2π+2σ] Cycloadditions of Bicyclo [1.1.0] butanes and Alkenes under Photo Conditions

Organic Letters, Journal Year: 2023, Volume and Issue: 25(45), P. 8116 - 8120

Published: Nov. 8, 2023

Hantzsch esters (HEs) are widely recognized as sources of hydride ions (H-) and sacrificial electron donors in their ground state. Here, we report the application HE a mediator [2π+2σ] cycloaddition bicyclo[1.1.0]butanes (BCBs) with alkenes under photo conditions. Through this strategy, various substituted bicyclo[2.1.1]hexanes can be efficiently prepared.

Language: 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, Journal Year: 2024, Volume and Issue: 146(29), P. 19621 - 19628

Published: May 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.

Language: Английский

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Three-dimensional saturated C(sp3)-rich bioisosteres for benzene

Nature Reviews Chemistry, Journal Year: 2024, Volume and Issue: 8(8), P. 605 - 627

Published: July 9, 2024

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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Double Strain-Release [2π+2σ]-Photocycloaddition

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(8), P. 5232 - 5241

Published: Feb. 13, 2024

In pursuit of potent pharmaceutical candidates and to further improve their chemical traits, small ring systems can serve as a potential starting point. Small units have the additional merit loaded strain at core, making them suitable reactants they capitalize on this intrinsic driving force. With introduction cyclobutenone strained precursor ketene, photocycloaddition with another unit, bicyclo[1.1.0]butane (BCB), enables reactivity both π-units in transient ketene. This double strain-release driven [2π+2σ]-photocycloaddition promotes synthesis diverse heterobicyclo[2.1.1]hexane units, pharmaceutically relevant bioisostere. The effective under catalyst-free conditions high functional group tolerance defines its synthetic utility. Experimental mechanistic studies density theory (DFT) calculations suggest that takes place via triplet mechanism.

Language: Английский

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Synthesis of 1-(Halo)alkyl-3-heteroaryl Bicyclo[1.1.1]pentanes Enabled by a Photocatalytic Minisci-type Multicomponent Reaction

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(8), P. 6247 - 6258

Published: April 10, 2024

Aryl-substituted bicyclo[1.1.1]pentane (BCP-aryl) derivatives represent the most important bioisosteres of biaryl scaffolds and widely exist in numerous complex pharmaceutical molecules. The current synthetic method limitations using only tertiary radical precursors, prefunctionalized heteroarenes, toxic transition metals, expensive photocatalysts make it urgent to develop a more simple practical protocol. To confront enrich Minisci-type chemistry, herein, we disclose photocatalytic multicomponent reaction for synthesis various (halo)alkyl BCP-aryls [1.1.1]propellane, alkyl halides, unfunctionalized heteroarenes as starting materials. Diverse kinds radicals (primary, secondary, carbons) derived from chlorides, bromides, fluoroalkyl iodides are very compatible this transformation. practicability is additionally boosted by product derivatizations late-stage functionalization pharmaceutically relevant mechanistic studies demonstrate that relay mechanism initiated consecutive photoinduced electron transfer (ConPET) process operation. We anticipate methodology would act useful tool biaryl-type drug derivatives, ultimately resulting great utility discovery program.

Language: Английский

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