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

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Recent Developments of Palladium- and Rhodium-Catalyzed β-Carbon Elimination Strategies

Synthesis, Journal Year: 2023, Volume and Issue: 55(15), P. 2285 - 2303

Published: Jan. 22, 2023

Abstract The activation of C–C bonds via transition metal catalysis has become an increasingly popular strategy in organic synthesis. An emerging method to cleave is facilitate a β-carbon elimination using rhodium or palladium catalysis. This elementary step typically relies on thermodynamic driving force, such as the relief ring strain steric strain. More recently, use neopentyl species chelation assistance enabled this difficult transformation. review will cover recent synthetic applications eliminations under and 1 Introduction 2 Chelation-Assisted β-Carbon Elimination Reactions 3 from Neopentyl–Pd Species 4 Pd-Catalyzed Catellani 5 Cyclopropanes 6 Conclusion

Language: Английский

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Mechanistic Investigation of the Rhodium-Catalyzed Transfer Hydroarylation Reaction Involving Reversible C–C Bond Activation

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(49), P. 26657 - 26666

Published: Nov. 30, 2023

Carbon-carbon (C-C) bonds are ubiquitous but among the least reactive in organic chemistry. Recently, catalytic approaches to activate C-C by transition metals have demonstrated synthetic potential of directly reorganizing skeleton small molecules. However, these usually restricted strained molecules or rely on directing groups, limiting their broader impact. We report a detailed mechanistic study rare example bond cleavage unstrained alcohols that enables reversible ketone transfer hydroarylation under Rh-catalysis. Combined insight from kinetic analysis, situ nuclear magnetic resonance (NMR) monitoring, and density functional theory (DFT) calculations supports symmetric cycle, including key β-carbon elimination event. In addition, we provide evidence regarding turnover-limiting step, catalyst resting state, role sterically encumbered NHC ligand. The further led an improved system with discovery two air-stable precatalysts showed higher activity for transformation comparison original conditions.

Language: Английский

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Stereodivergency in Copper‐Catalyzed Borylative Difunctionalizations: The Impact of Boron Coordination

Angewandte Chemie, Journal Year: 2024, Volume and Issue: 136(44)

Published: Aug. 13, 2024

Abstract A reagent‐controlled diastereodivergent copper‐catalyzed borylative difunctionalization is reported. The formation of Lewis adducts that guide selectivity commonly invoked in organic reaction mechanisms. Using density functional theory calculations, we identified BpinBdan as a sterically similar and less acidic alternative to B 2 pin . newly developed aldol domino the proof‐of‐concept, demonstrate change stereochemical outcome by simple borylating reagent—B affords diastereomer associated with coordination control while overturns this mode binding. We show strategy can be generalized other scaffolds and, more importantly, does not alter diastereomeric when involved. viewed mechanistic probe for future borylation reactions.

Language: Английский

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Stereodivergency in Copper‐Catalyzed Borylative Difunctionalizations: The Impact of Boron Coordination

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(44)

Published: Aug. 13, 2024

Abstract A reagent‐controlled diastereodivergent copper‐catalyzed borylative difunctionalization is reported. The formation of Lewis adducts that guide selectivity commonly invoked in organic reaction mechanisms. Using density functional theory calculations, we identified BpinBdan as a sterically similar and less acidic alternative to B 2 pin . newly developed aldol domino the proof‐of‐concept, demonstrate change stereochemical outcome by simple borylating reagent—B affords diastereomer associated with coordination control while overturns this mode binding. We show strategy can be generalized other scaffolds and, more importantly, does not alter diastereomeric when involved. viewed mechanistic probe for future borylation reactions.

Language: Английский

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