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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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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Strategies to Generate Nitrogen-centered Radicals That May Rely on Photoredox Catalysis: Development in Reaction Methodology and Applications in Organic Synthesis

Chemical Reviews, Год журнала: 2021, Номер 122(2), С. 2353 - 2428

Опубликована: Окт. 8, 2021

For more than 70 years, nitrogen-centered radicals have been recognized as potent synthetic intermediates. This review is a survey designed for use by chemists engaged in target-oriented synthesis. summarizes the recent paradigm shift access to and application of N-centered enabled visible-light photocatalysis. broadens streamlines approaches many small molecules because photocatalysis conditions are mild. Explicit attention paid innovative advances N–X bonds radical precursors, where X = Cl, N, S, O, H. clarity, key mechanistic data noted, available. Synthetic applications limitations summarized illuminate tremendous utility photocatalytically generated radicals.

Язык: Английский

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Phosphorus-Based Catalysis

ACS Central Science, Год журнала: 2021, Номер 7(4), С. 536 - 558

Опубликована: Март 16, 2021

Phosphorus-based organocatalysis encompasses several subfields that have undergone rapid growth in recent years. This Outlook gives an overview of its various aspects. In particular, we highlight key advances three topics: nucleophilic phosphine catalysis, organophosphorus catalysis to bypass oxide waste, and compound-mediated single electron transfer processes. We briefly summarize five additional chiral phosphoric acid Lewis base iminophosphorane super phosphonium salt phase frustrated pair catalysis. Although it is not catalytic nature, also discuss novel discoveries are emerging phosphorus(V) ligand coupling. conclude with some ideas about the future

Язык: Английский

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Main Group Redox Catalysis of Organopnictogens: Vertical Periodic Trends and Emerging Opportunities in Group 15

Journal of the American Chemical Society, Год журнала: 2021, Номер 143(4), С. 1699 - 1721

Опубликована: Янв. 19, 2021

A growing number of organopnictogen redox catalytic methods have emerged-especially within the past 10 years-that leverage plentiful reversible two-electron chemistry Group 15. The goal this Perspective is to provide readers context understand dramatic developments in catalysis over decade with an eye toward future development. An exposition fundamental differences atomic structure and bonding pnictogens, thus molecular electronic compounds, presented establish backdrop against which reactivity-and ultimately catalysis-is framed. deep appreciation these underlying periodic principles informs understanding differing modes evokes key challenges field moving forward. We close by addressing forward-looking directions likely animate area years come. What new manifolds can be developed through creative catalyst reaction design that take advantage intrinsic reactivity pnictogens drive discoveries catalysis?

Язык: Английский

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Electrochemically Enabled, Nickel-Catalyzed Dehydroxylative Cross-Coupling of Alcohols with Aryl Halides

Journal of the American Chemical Society, Год журнала: 2021, Номер 143(9), С. 3536 - 3543

Опубликована: Фев. 23, 2021

As alcohols are ubiquitous throughout chemical science, this functional group represents a highly attractive starting material for forging new C–C bonds. Here, we demonstrate that the combination of anodic preparation alkoxy triphenylphosphonium ion and nickel-catalyzed cathodic reductive cross-coupling provides an efficient method to construct C(sp2)–C(sp3) bonds, in which free aryl bromides—both readily available chemicals—can be directly used as coupling partners. This paired electrolysis reaction features broad substrate scope bearing wide gamut functionalities, was illustrated by late-stage arylation several structurally complex natural products pharmaceuticals.

Язык: Английский

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Recent advances in visible-light-mediated organic transformations in water

Green Chemistry, Год журнала: 2020, Номер 23(1), С. 232 - 248

Опубликована: Дек. 11, 2020

Water is a green reaction medium, while visible light represents renewable, clean, and abundant energy source. The recent advances in visible-light-mediated organic transformations water are summarized.

Язык: Английский

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Photocatalytic phosphine-mediated water activation for radical hydrogenation

Nature, Год журнала: 2023, Номер 619(7970), С. 506 - 513

Опубликована: Июнь 28, 2023

Abstract The chemical activation of water would allow this earth-abundant resource to be transferred into value-added compounds, and is a topic keen interest in energy research 1,2 . Here, we demonstrate with photocatalytic phosphine-mediated radical process under mild conditions. This reaction generates metal-free PR 3 –H 2 O cation intermediate, which both hydrogen atoms are used the subsequent transformation through sequential heterolytic (H + ) homolytic • cleavage two O–H bonds. –OH intermediate provides an ideal platform that mimics reactivity ‘free’ atom, can directly closed-shell π systems, such as activated alkenes, unactivated naphthalenes quinoline derivatives. resulting H adduct C radicals eventually reduced by thiol co-catalyst, leading overall transfer hydrogenation system, ending up product. thermodynamic driving force strong P=O bond formed phosphine oxide by-product. Experimental mechanistic studies density functional theory calculations support atom key step process.

Язык: Английский

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Sulfonium Salts as Acceptors in Electron Donor‐Acceptor Complexes

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(29)

Опубликована: Март 24, 2023

Abstract The photoactivation of electron donor‐acceptor complexes has emerged as a sustainable, selective and versatile strategy for the generation radical species. Electron (EDA) complexation, however, imposes electronic constraints on donor acceptor components this can limit range radicals that be generated using approach. New EDA complexation strategies exploiting sulfonium salts allow to from native functionality. For example, aryl salts, formed by activation arenes, serve in due their electron‐deficient nature. This “sulfonium tag” approach relaxes parent substrate dramatically expands complexation. In review, these new applications will introduced areas chemical space rendered accessible through innovation highlighted.

Язык: Английский

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Development of a General Organophosphorus Radical Trap: Deoxyphosphonylation of Alcohols

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(12), С. 7942 - 7949

Опубликована: Март 12, 2024

Here we report the design of a general, redox-switchable organophosphorus alkyl radical trap that enables synthesis broad range C(sp3)–P(V) modalities. This "plug-and-play" approach relies upon in situ activation alcohols and O═P(R2)H motifs, two broadly available inexpensive sources molecular complexity. The mild, photocatalytic deoxygenative strategy described herein allows for direct conversion sugars, nucleosides, complex pharmaceutical architectures to their analogs. includes facile incorporation medicinally relevant phosphonate ester prodrugs.

Язык: Английский

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