Photoinduced intermolecular hydrogen atom transfer reactions in organic synthesis

Chem Catalysis, Год журнала: 2021, Номер 1(3), С. 523 - 598

Опубликована: Май 24, 2021

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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Photoinduced Borylation for the Synthesis of Organoboron Compounds

Chemical Reviews, Год журнала: 2021, Номер 121(7), С. 3561 - 3597

Опубликована: Фев. 17, 2021

Organoboron compounds have important synthetic value and can be applied in numerous transformations. The development of practical convenient ways to synthesize boronate esters has thus attracted significant interest. Photoinduced borylations originated from stoichiometric reactions alkanes arenes with well-defined metal–boryl complexes. Now, photoredox-initiated borylations, catalyzed by either transition metal or organic photocatalysts, photochemical high efficiency become a burgeoning area research. In this Focus Review, we summarize research on photoinduced especially emphasizing recent developments trends. This includes the borylation arenes, alkanes, aryl/alkyl halides, activated carboxylic acids, amines, alcohols, so based catalysis, metal-free organocatalysis, direct activation. We focus reaction mechanisms involving single-electron transfer, triplet-energy other radical processes.

Язык: Английский

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Radical C(sp3)–H functionalization and cross-coupling reactions

Nature Reviews Chemistry, Год журнала: 2022, Номер 6(6), С. 405 - 427

Опубликована: Май 17, 2022

Язык: Английский

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Diversification of aliphatic C–H bonds in small molecules and polyolefins through radical chain transfer

Science, Год журнала: 2022, Номер 375(6580), С. 545 - 550

Опубликована: Фев. 3, 2022

The ability to selectively introduce diverse functionality onto hydrocarbons is of substantial value in the synthesis both small molecules and polymers. Herein, we report an approach aliphatic carbon-hydrogen bond diversification using radical chain transfer featuring easily prepared

Язык: Английский

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Site-Selective Direct C–H Pyridylation of Unactivated Alkanes by Triplet Excited Anthraquinone

Journal of the American Chemical Society, Год журнала: 2021, Номер 143(7), С. 3003 - 3012

Опубликована: Фев. 8, 2021

Site-selective C-H functionalization in chemical feedstocks is a challenging and useful reaction the broad field of research. Here, we report modular photochemical platform for site-selective pyridylation unactivated hydrocarbons via unique synergistic effects triplet excited anthraquinone an amidyl radical-based reverse hydrogen atom transfer (RHAT) agent. The selective tertiary secondary C(sp3)-H bonds abundant was achieved by employing various N-aminopyridinium salts highly fashion, thus providing new catalytic system direct construction high-value-added compounds under ambient conditions. Moreover, this operationally simple protocol applicable to variety linear-, branched-, cyclo-alkanes more complex molecules with high degrees site selectivity visible-light conditions, which provides rapid straightforward access versatile synthons upgrading mild, metal-free

Язык: Английский

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A cross-dehydrogenative C(sp3)−H heteroarylation via photo-induced catalytic chlorine radical generation

Nature Communications, Год журнала: 2021, Номер 12(1)

Опубликована: Июнь 29, 2021

Abstract Hydrogen atom abstraction (HAT) from C( sp 3 )–H bonds of naturally abundant alkanes for alkyl radical generation represents a promising yet underexplored strategy in the alkylation reaction designs since involving stoichiometric oxidants, excessive alkane loading, and limited scope are common drawbacks. Here we report photo-induced chemical oxidant-free cross-dehydrogenative coupling (CDC) between heteroarenes using catalytic chloride cobalt catalyst. Couplings strong bond-containing substrates complex heteroarenes, have been achieved with satisfactory yields. This dual platform features situ engendered chlorine exploits cobaloxime catalyst to enable hydrogen evolution turnover. The practical value this protocol was demonstrated by gram-scale synthesis alkylated heteroarene merely equiv. loading.

Язык: Английский

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Generation of non-stabilized alkyl radicals from thianthrenium salts for C–B and C–C bond formation

Nature Communications, Год журнала: 2021, Номер 12(1)

Опубликована: Июль 26, 2021

Abstract Sulfonium salts bearing a positively charged sulfur atom with three organic substituents have intrigued chemists for more than century their unusual structures and high chemical reactivity. These compounds are known to undergo facile single-electron reduction emerge as valuable alternative source of aryl radicals synthesis. However, the generation non-stabilized alkyl from sulfonium has been challenge several decades. Here we report treatment S -(alkyl) thianthrenium generate key intermediates granting controlled selective outcome ensuing reactions under mild photoredox conditions. The value these reagents demonstrated through efficient construction alkylboronates other transformations, including heteroarylation, alkylation, alkenylation, alkynylation. developed method is practical, provides opportunity convert C–OH bond C–B C–C bonds.

Язык: Английский

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Iron-Catalyzed C(Sp³)–H Borylation, Thiolation, and Sulfinylation Enabled by Photoinduced Ligand-to-Metal Charge Transfer

Journal of the American Chemical Society, Год журнала: 2023, Номер 145(13), С. 7600 - 7611

Опубликована: Март 23, 2023

Catalytic C(sp3)-H functionalization has provided enormous opportunities to construct organic molecules, facilitating the derivatization of complex pharmaceutical compounds. Within this framework, direct hydrogen atom transfer (HAT) photocatalysis becomes an appealing approach goal. However, viable substrates utilized in these protocols are limited, and site selectivity shows preference activated thermodynamically favored bonds. Herein, we describe development undirected iron-catalyzed borylation, thiolation, sulfinylation reactions enabled by photoinduced ligand-to-metal charge (LMCT) process. These exhibit remarkably broad substrate scope (>150 examples total), most importantly, all three show unconventional regioselectivity, with occurrence preferentially at distal methyl position. The procedures operationally simple readily scalable provide access high-value products from hydrocarbons one step. Mechanistic studies control experiments indicate that afforded is not only relevant HAT species but also largely affected use boron- sulfone-based radical acceptors.

Язык: Английский

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Photocatalytic three-component asymmetric sulfonylation via direct C(sp3)-H functionalization

Nature Communications, Год журнала: 2021, Номер 12(1)

Опубликована: Апрель 22, 2021

Язык: Английский

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