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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Cobalt/Salox‐Catalyzed Enantioselective C−H Functionalization of Arylphosphinamides

Angewandte Chemie International Edition, Год журнала: 2022, Номер 61(25)

Опубликована: Апрель 6, 2022

Previous methods on CoIII -catalyzed asymmetric C-H activation rely the use of tailor-made cyclopentadienyl-ligated complexes, which require lengthy steps for preparation. Herein, we report an unprecedented enantioselective functionalization enabled by a simple cobalt/salicyloxazoline (Salox) catalysis. The chiral Salox ligands can be easily prepared in one step from salicylonitrile and amino alcohols. A broad range P-stereogenic compounds were synthesized high yields with excellent enantioselectivities (45 examples, up to 99 % yield >99 ee). isolation characterization several intermediates provided insights into generation active catalytic cobalt species, action Salox, mode stereocontrol.

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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Atroposelective isoquinolinone synthesis through cobalt-catalysed C–H activation and annulation

Nature Synthesis, Год журнала: 2022, Номер 1(9), С. 709 - 718

Опубликована: Июль 18, 2022

Язык: Английский

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Single‐Step Synthesis of Atropisomers with Vicinal C−C and C−N Diaxes by Cobalt‐Catalyzed Atroposelective C−H Annulation

Angewandte Chemie International Edition, Год журнала: 2022, Номер 61(39)

Опубликована: Авг. 2, 2022

The atroposelective synthesis of atropisomers with vicinal diaxes remains rare and challenging, due to the steric influence between two axes their unique topology. Herein, we disclose a single-step construction C-C C-N chiral by cyclopentadiene (Cp)-free cobalt-catalyzed intramolecular C-H annulation, providing desired diaxial structures decent stereocontrols both (up >99 % ee 70 : 1 dr). optically pure products bearing fluorophores show circular polarized luminescence (CPL) properties, being candidate materials for potential CPL applications. Atropisomerization experiments density function theory (DFT) calculations are conducted study rotational barriers rotation pathways diaxes.

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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Cobalt‐Catalyzed Enantioselective C−H Carbonylation towards Chiral Isoindolinones

Angewandte Chemie International Edition, Год журнала: 2024, Номер 63(10)

Опубликована: Янв. 11, 2024

Transition metal-catalyzed enantioselective C-H carbonylation with carbon monoxide, an essential and easily available C1 feedstock, remains challenging. Here, we disclosed unprecedented catalyzed by inexpensive readily cobalt(II) salt. The reactions proceed efficiently through desymmetrization, kinetic resolution, parallel affording a broad range of chiral isoindolinones in good yields excellent enantioselectivities (up to 92 % yield 99 ee). synthetic potential this method was demonstrated asymmetric synthesis biological active compounds, such as (S)-PD172938 (S)-Pazinaclone. resulting also serve ligands cobalt-catalyzed annulation alkynes construct phosphorus stereocenter.

Язык: Английский

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Cobalt(III)-Catalyzed Enantioselective C–H Functionalization: Ligand Innovation and Reaction Development

Accounts of Chemical Research, Год журнала: 2025, Номер unknown

Опубликована: Фев. 26, 2025

ConspectusIn contrast to precious transition metals, such as palladium and rhodium, the development of novel chiral ligands for enantioselective C-H functionalizations catalyzed by earth-abundant, cost-effective, environmentally friendly 3d metals poses substantial challenges, primarily due variable oxidation states, intricate coordination patterns, limited mechanistic insights. In this Account, we summarize our research endeavors in three types Co(III) catalysis: pseudotetrahedral achiral Cp*Co(III)/chiral carbonyl acid (CCA) catalysis, situ-generated octahedral cobalt(III) via cobalt/salicyloxazoline (Salox) Co(II)/chiral phosphoric (CPA) cooperative achieved through strategic ligand design. Our initial objective was achieve functionalization Cp*Co(III) catalysts with external ligands, aiming circumvent laborious preparation CpxCo(III) complexes. To end, developed several CCA incorporating non-covalent interactions (NCIs) a crucial design element. Next, address limitations associated lengthy synthesis Cp-ligated complexes difficulties modification, explored concept situ generation catalysis using commercially available cobalt(II) salts tailor-made ligands. This exploration led two innovative catalytic systems, namely, Co(II)/Salox Co(II)/CCA sequential catalysis. The emerged versatile strategy, demonstrating excellent enantioselectivities across range asymmetric reactions construct various molecules central, axial, planar, inherent chirality. facile single step, along ease further enhances versatility applicability approach. Moreover, successfully applied cobalt/Salox electro- photochemical-catalyzed functionalization, electrons or oxygen traceless oxidant, thereby eliminating need stoichiometric chemical oxidants. Through studies reaction developments, elucidated detailed structure-enantioselectivity relationships which are expected inform future endeavors. Finally, Co(II)/CPA enabled spiro-γ-lactams olefination/asymmetric [4 + 1] spirocyclization. Mechanistically, establishment stereochemistry occurs during cyclization where CPA serves both neutral Brønsted acid, stereoinduction independent cleavage step. We anticipate that insights advancements Account will inspire innovations drive progress metal-catalyzed reactions.

Язык: Английский

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Cobalt/Salox‐Catalyzed Enantioselective Dehydrogenative C−H Alkoxylation and Amination

Angewandte Chemie International Edition, Год журнала: 2022, Номер 61(38)

Опубликована: Авг. 2, 2022

The past decade has witnessed a rapid progress in asymmetric C-H activation. However, the enantioselective alkoxylation and amination with alcohols free amines remains elusive. Herein, we disclose first dehydrogenative enabled by simple cobalt/salicyloxazoline (Salox) catalysis. use of cheap readily available cobalt(II) salts as catalysts Saloxs chiral ligands provides an efficient method to access P-stereogenic compounds excellent enantioselectivities (up >99 % ee). practicality this protocol is demonstrated gram-scale preparation further derivatizations resulting phosphinamides, which offering flexible alternative mono- diphosphine ligands. Preliminary mechanistic studies on reaction suggest that cobalt(III/IV/II) catalytic cycle might be involved.

Язык: Английский

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