Enantioselective electrochemical cobalt-catalyzed aryl C–H activation reactions

Science, Год журнала: 2023, Номер 379(6636), С. 1036 - 1042

Опубликована: Март 10, 2023

Enantioselective redox transformations typically rely on costly transition metals as catalysts and often stoichiometric amounts of chemical agents well. Electrocatalysis represents a more sustainable alternative, in particular through the use hydrogen evolution reaction (HER) place oxidant. In this work, we describe strategies for HER-coupled enantioselective aryl carbon-hydrogen bond (C-H) activation reactions using cobalt precious metal catalyst asymmetric oxidation. Thus, highly nitrogen-hydrogen (C-H N-H) annulations carboxylic amides were achieved, which gave access to point axially chiral compounds. Furthermore, cobalt-mediated electrocatalysis enabled preparation various phosphorus (P)-stereogenic compounds by selective desymmetrization dehydrogenative C-H reactions.

Язык: Английский

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TEMPO-Enabled Electrochemical Enantioselective Oxidative Coupling of Secondary Acyclic Amines with Ketones

Journal of the American Chemical Society, Год журнала: 2021, Номер 143(38), С. 15599 - 15605

Опубликована: Сен. 17, 2021

An electrochemical asymmetric coupling of secondary acyclic amines with ketones via a Shono-type oxidation has been described, affording the corresponding amino acid derivatives good to excellent diastereoselectivity and enantioselectivity. The addition an N-oxyl radical as redox mediator could selectively oxidize substrate rather than product, although their potential difference is subtle (about 13 mV). This transformation proceeds in absence stoichiometric additives, including metals, oxidants, electrolytes, which gives it functional group compatibility. Mechanistic studies suggest that proton-mediated racemization product prevented by reduction protons at cathode.

Язык: Английский

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Cobalt-Catalyzed Enantioselective C–H Arylation of Indoles

Journal of the American Chemical Society, Год журнала: 2022, Номер 144(2), С. 798 - 806

Опубликована: Янв. 10, 2022

Atropoisomeric (hetero)biaryls are scaffolds with increasing importance in the pharmaceutical and agrochemical industries. Although it is most obvious disconnection to construct such compounds, direct enantioselective C–H arylation through concomitant induction of chiral information remains extremely challenging uncommon. Herein, unprecedented earth-abundant 3d-metal-catalyzed atroposelective reported, furnishing rare atropoisomeric C2-arylated indoles. Kinetic studies DFT computation revealed an uncommon mechanism for this asymmetric transformation, oxidative addition being rate- enantio-determining step. Excellent stereoselectivities were reached (up 96% ee), while using unusual N-heterocyclic carbene ligand bearing essential remote substituent. Attractive dispersion interactions along positive C–H---π exerted by identified as key factors guarantee excellent enantioselection.

Язык: Английский

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Palladium-catalyzed enantioselective C–H functionalization via C–H palladation

Trends in Chemistry, Год журнала: 2022, Номер 4(3), С. 220 - 235

Опубликована: Янв. 20, 2022

Язык: Английский

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Enantio‐ and Regioselective Electrooxidative Cobalt‐Catalyzed C−H/N−H Annulation with Alkenes

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(11)

Опубликована: Янв. 20, 2023

In recent years, the merging of electrosynthesis with 3d metal catalyzed C-H activation has emerged as a sustainable and powerful technique in organic synthesis. Despite impressive advantages, development an enantioselective version remains elusive poses daunting challenge. Herein, we report first electrooxidative cobalt-catalyzed enantio- regioselective C-H/N-H annulation olefins using undivided cell at room temperature (up to 99 % ee). t Bu-Salox, rationally designed Salox ligand bearing bulky tert-butyl group ortho-position phenol, was found be crucial for this asymmetric reaction. A strong cooperative effect between Bu-Salox 3,4,5-trichloropyridine enabled highly more challenging α-olefins without secondary bond interactions 96 ee 97 : 3 rr). Cyclovoltametric studies, preparation, characterization, transformation cobaltacycle intermediates shed light on mechanism

Язык: Английский

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Catalytic Asymmetric Construction of Axially and Centrally Chiral Heterobiaryls by Minisci Reaction

Journal of the American Chemical Society, Год журнала: 2022, Номер 144(13), С. 6040 - 6049

Опубликована: Март 24, 2022

Axially chiral biaryls and heterobiaryls constitute the most represented subclass of atropisomers with prevalence in natural products, bioactive compounds, privileged ligand/catalysts, optically pure materials. Despite many ionic protocols for their construction, radical-based variants represent another highly desirable intriguing strategy but are far less developed. Moreover, efficient synthesis axially heterobiaryl molecules, especially ones having multiple heteroatoms other types elements, through radical routes remains extremely limited. We herein disclose first catalytic asymmetric, metal-free construction centrally by Minisci reaction 5-arylpyrimidines α-amino acid-derived redox-active esters. This is enabled use 4CzIPN as an organic photoredox catalyst conjunction a phosphoric acid catalyst. The achieved variety interesting featuring union α-branched amine generally excellent regio-, diastereo-, enantioselectivity (up to 82% yield; >19:1 dr; >99% ee). finding also builds up new platform development desymmetrization methods via radical-involved atroposelective functionalization at heteroarene prochiral heterobiaryls.

Язык: Английский

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Electrooxidative palladium- and enantioselective rhodium-catalyzed [3 + 2] spiroannulations

Chemical Science, Год журнала: 2022, Номер 13(9), С. 2783 - 2788

Опубликована: Янв. 1, 2022

Despite indisputable progress in the development of electrochemical transformations, electrocatalytic annulations for synthesis biologically relevant three-dimensional spirocyclic compounds has as yet not been accomplished. In sharp contrast, herein, we describe palladaelectro-catalyzed C-H activation/[3 + 2] spiroannulation alkynes by 1-aryl-2-naphthols. Likewise, a cationic rhodium(iii) catalyst was shown to enable electrooxidative [3 spiroannulations via formal C(sp3)-H activations. The versatile featured broad substrate scope, employing electricity green oxidant lieu stoichiometric chemical oxidants under mild conditions. An array enones and diverse spiropyrazolones, bearing all-carbon quaternary stereogenic centers were thereby accessed user-friendly undivided cell setup, with molecular hydrogen sole byproduct.

Язык: Английский

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Base‐Promoted Electrochemical Co^II‐catalyzed Enantioselective C−H Oxygenation

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(21)

Опубликована: Март 20, 2023

Metalla-electrocatalyzed C-H oxygenation represents one of the most straightforward and sustainable approaches to access valuable oxygenated molecules. Despite significant advances, development enantioselective electrochemical reaction is very challenging remains elusive. Herein, we described first CoII -catalyzed alkoxylation. A broad range enantioenriched alkoxylated phosphinamides were obtained in good yields with excellent enantioselectivities (up 98 % yield >99 ee). An unusual cobalt(III) alcohol complex was prepared fully characterized, which proven be a key intermediate this alkoxylation reaction. Mechanistic studies revealed that oxidation CoIII CoIV facilitated by base whole process proceeded through cobalt(III/IV/II) catalytic cycle.

Язык: Английский

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Nickel/biimidazole-catalyzed electrochemical enantioselective reductive cross-coupling of aryl aziridines with aryl iodides

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

Опубликована: Апрель 22, 2023

Here, we report an asymmetric electrochemical organonickel-catalyzed reductive cross-coupling of aryl aziridines with iodides in undivided cell, affording β-phenethylamines good to excellent enantioselectivity broad functional group tolerance. The combination cyclic voltammetry analysis the catalyst reduction potential as well electrode study provides a convenient route for reaction optimization. Overall, high efficiency this method is credited electroreduction-mediated turnover nickel instead metal reductant-mediated turnover. Mechanistic studies suggest radical pathway involved ring opening aziridines. statistical serves compare different design requirements photochemically and electrochemically mediated reactions under type mechanistic manifold.

Язык: Английский

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Enantioselective Synthesis of N‐N Atropisomers by Palladium‐Catalyzed C−H Functionalization of Pyrroles

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(21)

Опубликована: Март 21, 2023

The catalytic asymmetric construction of N-N atropisomeric biaryls remains a formidable challenge. Studies them lag far behind studies the more classical carbon-carbon biaryl atropisomers, hampering meaningful development. Herein, first palladium-catalyzed enantioselective C-H activation pyrroles for synthesis atropisomers is presented. Structurally diverse indole-pyrrole possessing chiral axis were produced with good yields and high enantioselectivities by alkenylation, alkynylation, allylation, or arylation reactions. Furthermore, kinetic resolution trisubstituted heterobiaryls sterically demanding substituents was also achieved. Importantly, this versatile functionalization strategy enables iterative exquisite selectivity, expediting formation valuable, complex, atropisomers.

Язык: Английский

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