Mechanistic Investigations of Cobalt-Catalyzed, Aminoquinoline-Directed C(sp²)–H Bond Functionalization

Journal of the American Chemical Society, Год журнала: 2025, Номер unknown

Опубликована: Янв. 10, 2025

Monoanionic, bidentate-auxiliary-directed, cobalt-catalyzed C–H bond functionalization has become a very useful tool in organic synthesis. A comprehensive investigation into isolated organometallic intermediates and their reactivity within the catalytic cycle is lacking. We report here mechanistic studies of cobalt-catalyzed, aminoquinoline-directed C(sp2)–H functionalization. number Co(III) have been structurally characterized, including, for first time aminoquinoline system, complexes arising from migratory insertion cobalt–carbon bonds. The stoichiometric reactions cobalt(III) aryls with alkenes, alkynes, carbon monoxide, cyclic secondary amines, benzamides explored. oxidation state cobalt product-forming step depends on nature coupling component. Specifically, annulation alkynes carbonylation CO likely proceed via Co(I)/Co(III) cycle. Carbon–hydrogen alkenes as well benzamide homocoupling, (formally) Co(IV) species involve oxidatively induced reductive elimination.

Язык: Английский

---

Insights into the mechanism of 3d transition-metal-catalyzed directed C(sp³)–H bond functionalization reactions

Chemical Society Reviews, Год журнала: 2025, Номер unknown

Опубликована: Янв. 1, 2025

This review provides an overview of the research advaces in Ni-, Cu-, Fe- and Co-catalyzed directed C(sp 3 )–H bond functionalization reactions; including design principles, mechanistic discussions, along with potential applications limitations.

Язык: Английский

---

Mechanism-Guided Development of Directed C–H Functionalization of Bicyclo[1.1.1]pentanes

Journal of the American Chemical Society, Год журнала: 2025, Номер unknown

Опубликована: Май 29, 2025

This report describes a detailed study of the palladium-mediated directed C(2)-H functionalization bicyclo[1.1.1]pentanes (BCPs). Previous attempts to achieve this transformation were reported as unsuccessful. To understand why, combination stoichiometric organometallic experiments (to isolate and coordination chemistry these substrates), H/D exchange directly probe C-H activation step), DFT calculations predict optimal directing groups supporting ligands) was conducted. Collectively, revealed that cyclometalation at Pd(II) is kinetically facile but thermodynamically unfavorable with aminoquinoline group acetonitrile ligand. However, changing pyridine N-oxide or dimethyl sulfoxide (DMSO) ligand enabled isolation stable BCP palladacycles. The complexes low-yielding two-electron aryl iodide oxidants. moving single-electron reactions (using in situ-generated radicals) electrophilic I2) resulted synthetically useful yields C(2)-functionalized products room temperature. approach leveraged access derivatives key intermediate synthesis bioisosteric analogues angiotensin II receptor blocker telmisartan. A four-step sequence from commercially available carboxylic acids, involving installation, cyclopalladation, C(2) arylation, cleavage, afforded comparable improved overall yield, step-count, functional compatibility relative state-of-the-art synthetic approaches. Overall, studies uncovered mild Pd-mediated route for C(2)-diversification scaffold. In addition, lessons learned herein provide blueprint achieving broader array strained ring benzene bioisosteres.

Язык: Английский

---

Exploration of Organometallic Cobalt Intermediates in an Aminoquinoline-Directed Dehydrogenative Dimerization Reaction

Organometallics, Год журнала: 2024, Номер unknown

Опубликована: Сен. 16, 2024

Язык: Английский

---