Visible Light-Driven Radical-Mediated C–C Bond Cleavage/Functionalization in Organic Synthesis

Chemical Reviews, Год журнала: 2020, Номер 121(1), С. 506 - 561

Опубликована: Май 29, 2020

Thermal C–C bond cleavage reactions allow the construction of structurally diverse molecular skeletons via predictable and efficient reorganizations. Visible light photoredox-catalyzed radical-mediated have recently emerged as a powerful alternative method for overcoming thermodynamic kinetic barrier in scaffolds. In recent years, plethora elegant useful been invented, products are sometimes otherwise inaccessible by classic thermal reactions. Considering great influence synthetic potential these reactions, we provide summary state art visible light-driven cleavage/functionalization strategies with specific emphasis on working models. We hoped that this review will be medicinal organic chemists inspire further reaction development interesting area.

Язык: Английский

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Photochemical and Electrochemical Applications of Proton-Coupled Electron Transfer in Organic Synthesis

Chemical Reviews, Год журнала: 2021, Номер 122(2), С. 2017 - 2291

Опубликована: Ноя. 23, 2021

We present here a review of the photochemical and electrochemical applications multi-site proton-coupled electron transfer (MS-PCET) in organic synthesis. MS-PCETs are redox mechanisms which both an proton exchanged together, often concerted elementary step. As such, MS-PCET can function as non-classical mechanism for homolytic bond activation, providing opportunities to generate synthetically useful free radical intermediates directly from wide variety common functional groups. introduction practitioner’s guide reaction design, with emphasis on unique energetic selectivity features that characteristic this class. then chapters oxidative N–H, O–H, S–H, C–H homolysis methods, generation corresponding neutral species. Then, reductive PCET activations involving carbonyl, imine, other X═Y π-systems, heteroarenes, where ketyl, α-amino, heteroarene-derived radicals be generated. Finally, we asymmetric catalysis materials device applications. Within each chapter, subdivide by group undergoing homolysis, thereafter type transformation being promoted. Methods published prior end December 2020 presented.

Язык: Английский

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Strategic Use of Visible-Light Photoredox Catalysis in Natural Product Synthesis

Chemical Reviews, Год журнала: 2021, Номер 122(2), С. 1717 - 1751

Опубликована: Июль 7, 2021

Recent progress in the development of photocatalytic reactions promoted by visible light is leading to a renaissance use photochemistry construction structurally elaborate organic molecules. Because rich functionality found natural products, studies product total synthesis provide useful insights into functional group compatibility these new methods as well their impact on synthetic strategy. In this review, we examine syntheses published through end 2020 that employ visible-light photoredox catalytic step. To assist someone interested employing steps discussed, review organized largely nature bond formed

Язык: Английский

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Advances in theE → ZIsomerization of Alkenes Using Small Molecule Photocatalysts

Chemical Reviews, Год журнала: 2021, Номер 122(2), С. 2650 - 2694

Опубликована: Авг. 27, 2021

Geometrical E → Z alkene isomerization is intimately entwined in the historical fabric of organic photochemistry and enjoying a renaissance (Roth et al. Angew. Chem., Int. Ed. Engl. 1989 28, 1193–1207). This consequence fundamental stereochemical importance Z-alkenes, juxtaposed with frustrations thermal reactivity that are rooted microscopic reversibility. Accessing excited state paradigms allow this latter obstacle to be circumnavigated by exploiting subtle differences photophysical behavior substrate product chromophores: provides molecular basis for directionality. While direct irradiation operationally simple, photosensitization via selective energy transfer enables augmentation repertoire include substrates not directly photons. Through sustained innovation, an impressive portfolio tailored small molecule catalysts range triplet energies now widely available facilitate contra-thermodynamic thermo-neutral reactions generate Z-alkene fragments. review intended serve as practical guide covering geometric alkenes enabled catalysis from 2000 2020, logical sequel excellent treatment Dugave Demange (Chem. Rev. 2003 103, 2475–2532). The mechanistic foundations underpinning selectivity discussed together induction models rationales explain counterintuitive directionality these processes which very distinguish product. Implications subsequent stereospecific transformations, application total synthesis, regioselective polyene isomerization, spatiotemporal control pre-existing configuration broader sense discussed.

Язык: Английский

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Alkoxy Radicals See the Light: New Paradigms of Photochemical Synthesis

Chemical Reviews, Год журнала: 2021, Номер 122(2), С. 2429 - 2486

Опубликована: Окт. 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.

Язык: Английский

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Light - driven deracemization enabled by excited - state electron transfer

Science, Год журнала: 2019, Номер 366(6463), С. 364 - 369

Опубликована: Окт. 17, 2019

Charging through the looking glass Asymmetric catalysis is a commonly applied technique to prepare just one of two mirror-image products in chemical reaction. But what if you already have compound want, stuck mixture left- and right-handed enantiomers? Shin et al. now show that light-induced electron transfer can trigger favorable succession proton hydrogen-atom steps, both which are susceptible biasing by catalysts, preferentially convert cyclic urea enantiomers into (see Perspective Wendlandt). Science , this issue p. 364 ; see also 304

Язык: Английский

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Radical‐Promoted C−C Bond Cleavage: A Deconstructive Approach for Selective Functionalization

Angewandte Chemie International Edition, Год журнала: 2019, Номер 58(40), С. 14044 - 14054

Опубликована: Июнь 6, 2019

Abstract Just as “Deconstructivism” appeared a novel movement in architecture the 1980s, deconstructive approaches have recently emerged excellent strategies for scaffold hopping modifications chemistry. The deconstruction and functionalization of cyclic molecules mainly involves cleavage carbon–carbon (C−C) bond followed by construction new bonds. inert C−C single bonds, especially unstrained cycles, their subsequent is still one most sought‐after challenges In this vein, radical‐mediated provide an approach achieving aim. This minireview outline history homolytic highlights recent advances exploring chemical space functionalization.

Язык: Английский

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Recent Advances in Photoredox‐Mediated Radical Conjugate Addition Reactions: An Expanding Toolkit for the Giese Reaction

Angewandte Chemie International Edition, Год журнала: 2021, Номер 60(39), С. 21116 - 21149

Опубликована: Фев. 25, 2021

Abstract Photomediated Giese reactions are at the forefront of radical chemistry, much like classical tin‐mediated were nearly forty years ago. With global recognition organometallic photocatalysts for mild and tunable generation carbon‐centered radicals, chemists have developed a torrent strategies to form previously inaccessible intermediates that capable engaging in intermolecular conjugate addition reactions. This Review summarizes advances photoredox‐mediated since 2013, with focus on breadth methods provide access crucial can engage processes.

Язык: Английский

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Boron-enabled geometric isomerization of alkenes via selective energy-transfer catalysis

Science, Год журнала: 2020, Номер 369(6501), С. 302 - 306

Опубликована: Июль 17, 2020

An E-Z boron swivel Compounds with carbon-carbon double bonds can form two distinct isomers, depending on whether the heaviest substituents both carbons lie same side (labeled Z) or diagonally across from each other E). Molloy et al. present a convenient method to reorient that bear and carbonyl substituents. When they are opposed, stay in plane, bond is easily swiveled by photosensitization. However, once as carbonyl, rotates out of plane further sensitization inhibited. Science this issue p. 302

Язык: Английский

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Cerium-Catalyzed C–H Functionalizations of Alkanes Utilizing Alcohols as Hydrogen Atom Transfer Agents

Journal of the American Chemical Society, Год журнала: 2020, Номер 142(13), С. 6216 - 6226

Опубликована: Март 17, 2020

Modern photoredox catalysis has traditionally relied upon metal-to-ligand charge-transfer (MLCT) excitation of metal polypyridyl complexes for the utilization light energy activation organic substrates. Here, we demonstrate catalytic application ligand-to-metal (LMCT) cerium alkoxide facile alkanes utilizing abundant and inexpensive trichloride as catalyst. As demonstrated by cerium-catalyzed C–H amination alkylation hydrocarbons, this reaction manifold enabled use alcohols practical selective hydrogen atom transfer (HAT) agents via direct access energetically challenging alkoxy radicals. Furthermore, LMCT event been investigated through a series spectroscopic experiments, revealing rapid bond homolysis process an effective production radicals, collectively ruling out LMCT/homolysis rate-determining step functionalization.

Язык: Английский

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