Ligand‐to‐Metal Charge Transfer (LMCT) Photochemistry at 3d‐Metal Complexes: An Emerging Tool for Sustainable Organic Synthesis

ChemCatChem, Год журнала: 2022, Номер 14(19)

Опубликована: Авг. 11, 2022

Abstract Despite the rich photochemistry of 3d‐metal complexes, utilization excited‐state reactivity these compounds in organic synthesis has been historically overlooked. The advent photoredox catalysis changed perception synthetic chemists towards photochemistry, and nowadays potential photoinduced, outer‐sphere single‐electron transfer events is widely recognized. More recently, an emerging new mode photoactivation taken spotlight, based on inner‐sphere triggered by population ligand‐to‐metal charge‐transfer (LMCT) excited states. Contrarily to photoredox, LMCT‐activation does not rely matching redox potentials, offers unique profiles particularly well suited Earth‐abundant metal complexes. Those appealing features are propelling development methods using this blueprint generate highly reactive open‐shell species under mild conditions. aim contribution provide a didactical tool for comprehension concept facilitate methodologies achieve sustainable chemical transformations.

Язык: Английский

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Electrophotocatalytic Decoupled Radical Relay Enables Highly Efficient and Enantioselective Benzylic C–H Functionalization

Journal of the American Chemical Society, Год журнала: 2022, Номер 144(47), С. 21674 - 21682

Опубликована: Ноя. 17, 2022

Asymmetric sp3 C–H functionalization has been demonstrated to substantially expedite target molecule synthesis, spanning from feedstocks upgradation late-stage modification of complex molecules. Herein, we report a highly efficient and sustainable method for enantioselective benzylic cyanation by merging electrophoto- copper catalysis. A novel catalytic system allows one independently regulate the hydrogen atom transfer step radical formation speciation Cu(II)/Cu(I) effectively capture transient intermediate, through tuning electronic property anthraquinone-type photocatalyst simply modulating applied current, respectively. Such decoupled relay catalysis enables unified approach diverse alkylarenes, many which are much less reactive or even unreactive using existing relying on coupled relay. Moreover, current protocol is also amenable bioactive molecules, including natural products drugs.

Язык: Английский

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Carbon-centered radical capture at nickel(II) complexes: Spectroscopic evidence, rates, and selectivity

Chem, Год журнала: 2023, Номер 9(5), С. 1295 - 1308

Опубликована: Март 13, 2023

Язык: Английский

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Enantioselective C(sp³)–C(sp³) Reductive Cross-Electrophile Coupling of Unactivated Alkyl Halides with α-Chloroboronates via Dual Nickel/Photoredox Catalysis

Journal of the American Chemical Society, Год журнала: 2023, Номер 145(4), С. 2081 - 2087

Опубликована: Янв. 23, 2023

Substantial advances in enantioconvergent C(sp3)-C(sp3) bond formations have been made with nickel-catalyzed cross-coupling of racemic alkyl electrophiles organometallic reagents or nickel-hydride-catalyzed hydrocarbonation alkenes. Herein, we report an unprecedented enantioselective reductive by the direct utilization two different halides dual nickel/photoredox catalysis system. This highly selective coupling α-chloroboronates and unactivated iodides furnishes chiral secondary boronic esters, which serve as useful important intermediates realm organic synthesis enable a desirable protocol to fast construction enantioenriched complex molecules.

Язык: Английский

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Site- and enantioselective cross-coupling of saturated N-heterocycles with carboxylic acids by cooperative Ni/photoredox catalysis

Nature Communications, Год журнала: 2023, Номер 14(1)

Опубликована: Янв. 9, 2023

Abstract Site- and enantioselective cross-coupling of saturated N -heterocycles carboxylic acids—two the most abundant versatile functionalities—to form pharmaceutically relevant α-acylated amine derivatives remains a major challenge in organic synthesis. Here, we report general strategy for highly site- α-acylation with situ-activated acids. This modular approach exploits hydrogen-atom-transfer reactivity photocatalytically generated chlorine radicals combination asymmetric nickel catalysis to selectively functionalize cyclic α-amino C−H bonds presence benzylic, allylic, acyclic α-amino, α-oxy methylene groups. The mild scalable protocol requires no organometallic reagents, displays excellent chemo-, enantioselectivity, is amenable late-stage diversification, including synthesis previously inaccessible Taxol derivatives. Mechanistic studies highlight exceptional versatility chiral catalyst orchestrating (i) catalytic elimination, (ii) alkyl radical capture, (iii) cross-coupling, (iv) induction.

Язык: Английский

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Enantioselective C(sp³)–H Functionalization of Oxacycles via Photo-HAT/Nickel Dual Catalysis

Journal of the American Chemical Society, Год журнала: 2023, Номер 145(9), С. 5231 - 5241

Опубликована: Фев. 22, 2023

The selective functionalization of ubiquitous but inert C-H bonds is highly appealing in synthetic chemistry, the direct transformation hydrocarbons lacking directing groups into high-value chiral molecules remains a formidable challenge. Herein, we develop an enantioselective C(sp3)-H undirected oxacycles via photo-HAT/nickel dual catalysis. This protocol provides practical platform for rapid construction and enantiomerically enriched directly from simple abundant hydrocarbon feedstocks. utility this strategy further demonstrated late-stage natural products synthesis many pharmaceutically relevant molecules. Experimental density functional theory calculation studies provide detailed insights mechanism origin enantioselectivity asymmetric functionalization.

Язык: Английский

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Nickel-catalysed enantioselective alkene dicarbofunctionalization enabled by photochemical aliphatic C–H bond activation

Nature Catalysis, Год журнала: 2024, Номер 7(6), С. 655 - 665

Опубликована: Апрель 29, 2024

Abstract The development of novel strategies to rapidly construct complex chiral molecules from readily available feedstocks is a long-term pursuit in the chemistry community. Radical-mediated alkene difunctionalizations represent an excellent platform towards this goal. However, asymmetric versions remain highly challenging, and more importantly, examples featuring simple hydrocarbons as reaction partners are elusive. Here we report three-component dicarbofunctionalization capitalizing on direct activation C( sp 3 )–H bonds through combination photocatalysed hydrogen atom transfer nickel catalysis. This protocol provides efficient for installing two vicinal carbon–carbon across alkenes atom-economic fashion, providing wide array high-value α-aryl/alkenyl carbonyls phosphonates, well 1,1-diarylalkanes ubiquitous alkane, ether alcohol feedstocks. method exhibits operational simplicity, broad substrate scope regioselectivity, chemoselectivity enantioselectivity. compatibility with bioactive motifs expedient synthesis pharmaceutically relevant highlight synthetic potential protocol.

Язык: Английский

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Photocatalyzed Enantioselective Functionalization of C(sp³)–H Bonds

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(2), С. 1209 - 1223

Опубликована: Янв. 3, 2024

Owing to its diverse activation processes including single-electron transfer (SET) and hydrogen-atom (HAT), visible-light photocatalysis has emerged as a sustainable efficient platform for organic synthesis. These provide powerful avenue the direct functionalization of C(sp3)–H bonds under mild conditions. Over past decade, there have been remarkable advances in enantioselective bond via combined with conventional asymmetric catalysis. Herein, we summarize involving discuss two main pathways this emerging field: (a) SET-driven carbocation intermediates are followed by stereospecific nucleophile attacks; (b) photodriven alkyl radical further enantioselectively captured (i) chiral π-SOMOphile reagents, (ii) stereoselective transition-metal complexes, (iii) another distinct stereoscopic species. We aim key reaction design, catalyst development, mechanistic understanding, new insights into rapidly evolving area research.

Язык: Английский

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Mechanism of Ni-Catalyzed Photochemical Halogen Atom-Mediated C(sp³)–H Arylation

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(22), С. 15331 - 15344

Опубликована: Май 23, 2024

Within the context of Ni photoredox catalysis, halogen atom photoelimination from has emerged as a fruitful strategy for enabling hydrogen transfer (HAT)-mediated C(sp3)–H functionalization. Despite numerous synthetic transformations invoking this paradigm, unified mechanistic hypothesis that is consistent with experimental findings on catalytic systems and accounts radical formation facile C(sp2)–C(sp3) bond remains elusive. We employ kinetic analysis, organometallic synthesis, computational investigations to decipher mechanism prototypical Ni-catalyzed photochemical arylation reaction. Our revise previous proposals, first by examining relevance SET EnT processes intermediates relevant HAT-based investigation highlights ability blue light promote efficient Ni–C(sp2) homolysis cationic NiIII reductive elimination bipyridine NiII complexes. However interesting, rates selectivities these do not account productive pathway. Instead, our studies support involves evolution in situ generated dihalide intermediates, capture NiII(aryl)(halide) resting state, key C–C NiIII. Oxidative addition NiI, opposed Ni0, rapid NiIII/NiI comproportionation play roles process. The presented herein offer fundamental insight into reactivity broader catalysis.

Язык: Английский

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Enantioselective alkylation of α-amino C(sp3)−H bonds via photoredox and nickel catalysis

Nature Catalysis, Год журнала: 2024, Номер 7(8), С. 889 - 899

Опубликована: Июль 4, 2024

Язык: Английский

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