Alkoxy Radicals See the Light: New Paradigms of Photochemical Synthesis

Chemical Reviews, Journal Year: 2021, Volume and Issue: 122(2), P. 2429 - 2486

Published: Oct. 6, 2021

Alkoxy radicals are highly reactive species that have long been recognized as versatile intermediates in organic synthesis. However, their development has impeded due to a lack of convenient methods for generation. Thanks advances photoredox catalysis, enabling facile access alkoxy from bench-stable precursors and free alcohols under mild conditions, research interest this field renewed. This review comprehensively summarizes the recent progress radical-mediated transformations visible light irradiation. Elementary steps radical generation either or central reaction development; thus, each section is categorized discussed accordingly. Throughout review, we focused on different mechanisms well impact synthetic utilizations. Notably, catalytic abundant still early stage, providing intriguing opportunities exploit diverse paradigms.

Language: Английский

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Selective Degradation of Styrene‐Related Plastics Catalyzed by Iron under Visible Light**

ChemSusChem, Journal Year: 2021, Volume and Issue: 14(22), P. 5049 - 5056

Published: Sept. 12, 2021

Abstract Efficient degradation of plastics, the vital challenge for a sustainable future, stands in need better chemical recycling procedures that help produce commercially valuable small molecules and redefine plastic waste as rich source feedstock. However, corresponding methods, while being generally restricted to polar polymers, improvement. Particularly, chemically inert nonpolar major constitutes suffers from low selectivity very harsh transformation conditions. Herein, an efficient method was developed selective styrene‐related plastics under gentle conditions through multiple oxidation sp 3 C−H bonds C−C bonds. The procedure catalyzed with inexpensive iron salts visible light, using oxygen green oxidant. Furthermore, simple could be used degrade absence solvent natural conditions, highlighting potential application additives degradable plastics.

Language: Английский

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Deconstructive Synthesis of Bridged and Fused Rings via Transition-Metal-Catalyzed “Cut-and-Sew” Reactions of Benzocyclobutenones and Cyclobutanones

Accounts of Chemical Research, Journal Year: 2022, Volume and Issue: 55(16), P. 2341 - 2354

Published: July 28, 2022

ConspectusBridged and fused rings are commonly found in biologically important molecules. Current tactics to construct these ring systems primarily based on stepwise formation (i.e., making one first followed by another) cycloaddition reactions (e.g., Diels–Alder reaction). To seek a complementary perhaps more unified ring-forming approach, deconstructive strategy C–C bond activation of cyclic ketones has been conceived. The named "cut-and-sew" reaction uses with tethered unsaturated moiety as substrates, which involves oxidative addition transition metal into the ketone intramolecular insertion unit. This proved successful access diverse scaffolds that nontrivial otherwise.This Account offers concise summary our laboratory's systematic efforts developing metal-catalyzed cut-and-sew for synthesis bridged over past 10 years. In particular, we will focus using readily available benzocyclobutenones cyclobutanones. date, scope greatly expanded. First, moieties can serve suitable coupling partners, such alkenyl, alkynyl, allenyl, carbonyl, iminyl groups. Second, variety modes have uncovered. this account, (4 + 2), 2 – 1), 1) cycloadditions lead range or be summarized. Third, enantioselective transformations realized efficiently chiral scaffolds, enabled two strategies: enantio-determining migratory desymmetrization Fourth, synthetic applications demonstrated streamlined total syntheses number complex natural products. Compared conventional logics, allows development new bond-disconnecting strategies. Thus, (−)-cycloclavine, (−)-thebainone A, penicibilaenes, proposed cycloinumakiol discussed detail.In narrative chemistry, also aims provide core guiding foundations inspirations toward broader through cleavage. It is anticipated classes compounds could substrates beyond cyclobutanones, coupled. envisaged innovative utilization organic revealed near future.

Language: Английский

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Construction of C−S and C−Se Bonds from Unstrained Ketone Precursors under Photoredox Catalysis

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(8)

Published: Jan. 8, 2024

A mild photoredox catalyzed construction of sulfides, disulfides, selenides, sulfoxides and sulfones from unstrained ketone precursors is introduced. Combination this deacylative process with S

Language: Английский

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N‐Atom Deletion in Nitrogen Heterocycles

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 60(38), P. 20678 - 20683

Published: July 6, 2021

Abstract Excising the nitrogen in secondary amines, and coupling two residual fragments is a skeletal editing strategy that can be used to construct molecules with new skeletons, but which has been largely unexplored. Here we report versatile method of N‐atom excision from N‐heterocycles. The process uses readily available N‐heterocycles as substrates, proceeds by N‐sulfonylazidonation followed rearrangement sulfamoyl azide intermediates, providing various cyclic products. Examples are provided deletion natural products, synthesis chiral O‐heterocycles commercially β‐amino alcohols, formal inert C−H functionalization through sequence N‐directed reactions serve traceless directing group.

Language: Английский

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Rhodium Catalyzed Regioselective C−H Allylation of Simple Arenes via C−C Bond Activation of Gem‐difluorinated Cyclopropanes

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 60(19), P. 10626 - 10631

Published: Feb. 18, 2021

Herein, we report a rhodium catalyzed directing-group free regioselective C-H allylation of simple arenes. Readily available gem-difluorinated cyclopropanes can be employed as highly reactive allyl surrogates via sequence C-C and C-F bond activation, providing arene derivatives in good yields with high regioselectivity under mild conditions. The robust methodology enables facile late-stage functionalization complex bioactive molecules. efficiency this reaction is also demonstrated by the turnover number (TON, up to 1700) catalyst on gram-scale experiments. Preliminary success kinetic resolution transformation achieved, promising access enantio-enriched cyclopropanes.

Language: Английский

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Directing-group-free catalytic dicarbofunctionalization of unactivated alkenes

Nature Chemistry, Journal Year: 2021, Volume and Issue: 14(2), P. 188 - 195

Published: Dec. 13, 2021

Language: Английский

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A Flexible and Degradable Hybrid Mineral as a Plastic Substitute

Advanced Materials, Journal Year: 2021, Volume and Issue: 34(9)

Published: Dec. 28, 2021

The development of environmentally friendly plastics is critical to ensure sustainable development. In contrast polymer derived from petrochemicals, inorganic minerals, which are the most abundant matter in Earth's crust, friendly. However, brittleness these minerals limits their applications as plastics. Here, because advantages both biomineralization and ionic polymerization, calcium phosphate (CaP, a typical geological biological mineral) oligomers used for biomimetic mineralization under regulation polyvinyl alcohol sodium alginate, resulting flexible CaP nanofibers with periodic structural defects. assembly produces hierarchically structured bulk hybrid mineral (HM), overcomes intrinsic exhibits plasticity characteristics. HM better hardness thermostability than classical due its dominant composition. Notably, degradable nature, it can potentially participate cycles, indicating that this material an optimal plastic substitute. construction defects within expands current understanding materials science.

Language: Английский

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Biocatalytic One-Carbon Ring Expansion of Aziridines to Azetidines via a Highly Enantioselective [1,2]-Stevens Rearrangement

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(11), P. 4739 - 4745

Published: March 8, 2022

We report enantioselective one-carbon ring expansion of aziridines to make azetidines as a new-to-nature activity engineered "carbene transferase" enzymes. A laboratory-evolved variant cytochrome P450BM3, P411-AzetS, not only exerts unparalleled stereocontrol (99:1 er) over [1,2]-Stevens rearrangement but also overrides the inherent reactivity aziridinium ylides, cheletropic extrusion olefins, perform rearrangement. By controlling fate highly reactive ylide intermediates, these evolvable biocatalysts promote transformation which cannot currently be performed using other catalyst classes.

Language: Английский

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Dihydroquinazolinones as adaptative C(sp3) handles in arylations and alkylations via dual catalytic C–C bond-functionalization

Nature Communications, Journal Year: 2022, Volume and Issue: 13(1)

Published: May 3, 2022

Abstract C–C bond forming cross-couplings are convenient technologies for the construction of functional molecules. Consequently, there is continual interest in approaches that can render traditionally inert functionality as cross-coupling partners, included this ketones which widely-available commodity chemicals and easy to install synthetic handles. Herein, we describe a dual catalytic strategy utilizes dihydroquinazolinones derived from ketone congeners adaptative one-electron handles forging C( sp 3 ) architectures via α cleavage with aryl alkyl bromides. Our approach achieved by combining flexibility modularity nickel catalysis propensity photoredox events generating open-shell reaction intermediates. This method distinguished its wide scope broad application profile––including chemical diversification advanced intermediates––, providing technique complementary existing reactions operates within bond-functionalization arena.

Language: Английский

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