Sulfamate Esters Guide C(3)-Selective Xanthylation of Alkanes

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

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“…103 °C) which favors a seven-membered-ring transition state over the usual six-membered-ring. 241 , 242 …”

Section: N -Centered Radical Generation From N–h Bonds Through Photochemical and Electrochemical Pcet Processesmentioning

confidence: 99%

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

et al. 2021

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“…Cognizant of the emergence of sulfamyl radical‐directed halogen‐ [167, 168] and group‐transfer reactions, [169–171] Roizen and co‐workers, [172] Duan and co‐workers, [173] and Shu et al [174] have demonstrated that sulfamate esters [175] can serve as direct precursors to radicals under photochemical conditions (Scheme 45). The accessed sulfamyl radicals guide Giese reactions based on remarkable 1,6‐HAT processes, which proceed with site‐selectivity that has been historically inaccessible.…”

Section: Nitrogen‐centered Radicals Enable Hydrogen‐atom‐transfer Processes To Generate Remote Carbon‐centered Radicalsmentioning

confidence: 99%

“…[166] As ademonstration of synthetic value,subsequent hydrolysis of the imine to the ketone provides technology for obtaining g-C(sp 3 )-H functionalized ketones.A lternatively,t he versatile imine functionality can be retained through at wo-step, one-pot protection with benzoyl chloride. Cognizant of the emergence of sulfamyl radical-directed halogen- [167,168] and group-transfer reactions, [169][170][171] Roizen and co-workers, [172] Duan and co-workers, [173] and Shu et al [174] have demonstrated that sulfamate esters [175] can serve as direct precursors to radicals under photochemical conditions (Scheme 45). Thea ccessed sulfamyl radicals guide Giese reactions based on remarkable 1,6-HATp rocesses,w hich proceed with site-selectivity that has been historically inaccessible.…”

Section: Iminyl Radicals Direct Giese Reactionsmentioning

confidence: 99%

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

2021

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

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Section: Iminyl Radicals Direct Giese Reactionsmentioning

confidence: 99%

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

Kanegusuku

Roizen

2021

Angewandte Chemie

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10. Alkoxyl radicals enable 1,5-HAT processes to generate carbon-centered radicals 21310 11. Direct hydrogen-atom abstraction of non-reactive C(sp 3 )ÀHb onds generates carbon-centered radicals 21312 12. Summary and Outlook 21313 Scheme 1. Until recently,most Giese reactions relied on tin hydride, or tin hydride and AIBN. Conditions were tuned to minimizep otentially competitive off-pathwayr eactions.

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Sulfamate Esters Guide C(3)-Selective Xanthylation of Alkanes

Cited by 36 publications

References 96 publications

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

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

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

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

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