Cobalt(II)-Catalyzed C–H Alkylation of N-Heterocycles with 1,4-Dihydropyridines

ACS Catalysis, Год журнала: 2022, Номер 12(24), С. 15707 - 15714

Опубликована: Дек. 7, 2022

The rapid incorporation of alkyl and acyl groups into C–H bonds N-heterocycles is in demand for the development lead candidates drug discovery. Herein, we report cobalt(II)-catalyzed alkylation acylation with 1,4-dihydropyridines (DHPs) as alkylating acylating agents. Notably, a combination KBrO3 Co(II) catalyst was successfully employed generation radicals from DHPs. A series heterocycles, including azauracils, quinoxalinones, pyrazinones, pyridones, quinolones, quinazolinones, xanthines, chromones, azine N-oxides, were compatible under developed conditions. applicability protocol challenging contexts highlighted by selective modification well gram-scale synthesis bioactive molecules. Combined mechanistic investigations aided elucidation plausible reaction mechanism.

Язык: Английский

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Reversal of Regioselectivity in Asymmetric C−H Bond Annulation with Bromoalkynes under Cobalt Catalysis**

Angewandte Chemie International Edition, Год журнала: 2023, Номер 63(6)

Опубликована: Дек. 14, 2023

Abstract Metal‐catalyzed asymmetric C−H bond annulation strategy offers a versatile platform, allowing the construction of complex P‐chiral molecules through atom‐ and step‐economical fashion. However, regioselective insertion π‐coupling partner between M−C with high enantio‐induction remain elusive. Using commercially available Co(II) salt chiral‐Salox ligands, we demonstrate an unusual protocol for regio‐reversal, enantioselective phosphinamide bromoalkyne desymmetrization. The reaction proceeds ligand‐assisted enantiodetermining cyclocobaltation followed by Co−C, subsequent reductive elimination, halogen exchange carboxylate resulted in P‐stereogenic compounds excellent ee (up to >99 %). isolation cobaltacycle involved catalytic cycle outcome control experiments provide support plausible mechanism.

Язык: Английский

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Traceless Bidentate Directing Group Assisted Cobalt-Catalyzed sp²-C–H Activation and [4 + 2]-Annulation Reaction with 1,3-Diynes

Organic Letters, Год журнала: 2020, Номер 22(19), С. 7480 - 7485

Опубликована: Сен. 16, 2020

An efficient cobalt-catalyzed [4 + 2] annulation of hydrazones and 1,3-diynes has been developed for the synthesis 3-alkynylated isoquinolines engaging 2-aminopyridine as a traceless bidentate directing group. The strategy successfully extended 3,3′-biisoquinoline moieties via both one-pot well sequential approaches. utilization group with an inexpensive earth-abundant cobalt-catalyst under operationally simple reaction conditions makes present transformation more valuable appealing.

Язык: Английский

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Room-Temperature Synthesis of Isoindolone Spirosuccinimides: Merger of Visible-Light Photocatalysis and Cobalt-Catalyzed C–H Activation

The Journal of Organic Chemistry, Год журнала: 2020, Номер 85(23), С. 15287 - 15304

Опубликована: Ноя. 3, 2020

A room-temperature C–H bond functionalization of benzamides has been developed by merging a photocatalyst with cobalt catalyst for the synthesis isoindolone spirosuccinimides. The reaction proceeds in aerobic conditions and does not require any sacrificial external oxidants such as Ag(I) or Mn(III) salts. Visible light activates photocatalyst, it acts an electron-transfer reagent helps fundamental organometallic steps modulating oxidation state complex. This spirocyclization showed wide substrate scope good functional group tolerance. possible mechanism was proposed from experimental outcome, showing that activation is irreversible rate-determining step.

Язык: Английский

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Cobalt-catalyzed carbonylation of the C–H bond

Organic & Biomolecular Chemistry, Год журнала: 2020, Номер 18(38), С. 7460 - 7466

Опубликована: Янв. 1, 2020

Direct carbonylation of the C-H bond is a great tool for installing carbonyl group in wide variety substrates. This review summarizes methodologies using cobalt-catalyzed functionalization approach. Despite fact that have been known since Murahashi's report 1955, this area still underdeveloped, particularly C(sp3)-H bond.

Язык: Английский

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