Cobalt-Catalyzed Enantioselective C–H Annulation with Alkenes

ACS Catalysis, Journal Year: 2023, Volume and Issue: 13(7), P. 4250 - 4260

Published: March 13, 2023

Herein, we disclose an efficient cobalt-catalyzed enantioselective C–H activation and annulation of benzamides with alkenes. This transformation is facilitated via the commercially available cobalt(II) catalyst in presence easily prepared chiral salicyl-oxazoline (Salox) ligand, which provides facile access to (R) or (S) enantiomers dihydroisoquinolone derivatives. It noticeable that reaction proceeded efficiently within extremely short time from 10 30 min under mild conditions. A broad range alkenes bear various functional substituents have been shown good compatibility deliver targeted products high yields enantioselectivities (51 examples, up 98% yield 99% ee). The gram scale experiment removal directing group further demonstrate practicability this protocol potential industrial applications. Density theory calculations elucidate mechanism, spin-state change olefin insertion step accelerates subsequent C–N reductive elimination, identified as stereo-determining step. AIM analysis indicates π interactions are vital for controlling switching stereoselectivity.

Language: Английский

---

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

Accounts of Chemical Research, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 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.

Language: Английский

---

Cobalt–N-Heterocyclic Carbene Complexes in Catalysis

ACS Catalysis, Journal Year: 2022, Volume and Issue: 12(5), P. 3111 - 3137

Published: Feb. 21, 2022

Cobalt–N-heterocyclic carbene (NHC) complexes have emerged as an attractive class of 3d transition metal catalysts for a broad range chemical processes, including cross-coupling, hydrogenation, hydrofunctionalization, and cycloaddition reactions. Herein, we present comprehensive review catalytic methods utilizing cobalt–NHC with focus on the catalyst structure, role NHC ligand, properties system, mechanism, synthetic utility. The survey clearly suggests that recent emergence well-defined may tremendous utility in design application reactions using more abundant metals.

Language: Английский

---

Enantioselective C−H functionalization reactions enabled by cobalt catalysis

Chem Catalysis, Journal Year: 2022, Volume and Issue: 2(11), P. 2965 - 2985

Published: Sept. 16, 2022

Language: Английский

---

C–H bond activation and sequential addition to two different coupling partners: a versatile approach to molecular complexity

Chemical Society Reviews, Journal Year: 2022, Volume and Issue: 51(15), P. 6738 - 6756

Published: Jan. 1, 2022

Sequential multicomponent C–H bond addition is a powerful approach for the rapid, modular generation of molecular complexity in single reaction.

Language: Английский

---

Three-Component Coupling of Arenes, Ethylene, and Alkynes Catalyzed by a Cationic Bis(phosphine) Cobalt Complex: Intercepting Metallacyclopentenes for C–H Functionalization

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(10), P. 4530 - 4540

Published: March 4, 2022

A cobalt-catalyzed intermolecular three-component coupling of arenes, ethylene, and alkynes was developed using the well-defined air-stable cationic bis(phosphine) cobalt(I) complex, [(dcype)Co(η6-C7H8)][BArF4] (dcype = 1,2-bis(dicyclohexylphosphino)ethane; BArF4 B[(3,5-(CF3)2)C6H3]4), as precatalyst. All three components were required for turnover formation ortho-homoallylated arene products. range directing groups including amide, ketone, 2-pyridyl substituents on promoted reaction. The method exhibited broad functional group tolerance allowing late-stage functionalization two drug molecules, fenofibrate haloperidol. series control reactions, deuterium labeling studies, resting state analysis, well synthesis substrate- product-bound η6-arene complexes supported a pathway involving C(sp2)–H activation from cobalt(III) metallacycle.

Language: Английский

---

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

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 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.

Language: Английский

---

Parametrization of κ²-N,O-Oxazoline Preligands for Enantioselective Cobaltaelectro-Catalyzed C–H Activations

ACS Catalysis, Journal Year: 2025, Volume and Issue: unknown, P. 4450 - 4459

Published: Feb. 28, 2025

Enantioselective electrocatalyzed C–H activations have emerged as a transformative platform for the assembly of value-added chiral organic molecules. Despite recent progress, construction multiple C(sp3)-stereogenic centers via C(sp3)–C(sp3) bond formation has thus far proven to be elusive. In contrast, we herein report an annulative activation strategy, generating Fsp3-rich molecules with high levels diastereo- and enantioselectivity. κ2-N,O-oxazoline preligands were effectively employed in enantioselective cobalt(III)-catalyzed reactions. Using DFT-derived descriptors regression statistical modeling, performed parametrization study on modularity preligands. The resulted model describing ligands' selectivity characterized by key steric, electronic, interaction behaviors.

Language: Английский

---

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

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 63(6)

Published: Dec. 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.

Language: Английский

---

Cobalt catalyzed alkenylation/annulation reactions of alkynes via C–H activation: A review

Tetrahedron, Journal Year: 2023, Volume and Issue: 132, P. 133248 - 133248

Published: Jan. 9, 2023

Language: Английский

---