Origins of Catalyst Inhibition in the Manganese‐Catalysed Oxidation of Lignin Model Compounds with H<sub>2</sub>O<sub>2</sub>

Barbieri, Alessia; Kasper, Johann B.; Mecozzi, Francesco; Lanzalunga, Osvaldo; Browne, Wesley R.

doi:10.1002/cssc.201900689

Cited by 10 publications

(3 citation statements)

References 58 publications

(122 reference statements)

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“…We envision that the present results, beyond improving fundamental knowledge of Cu-dioxygen reactivity, will find some crucial application in the field of copper catalysis. In particular, aryl ether linkages are important targets found in numerous biomolecules as lignin . Future work in our laboratory will be devoted to the transfer of this reactivity toward external substrates.…”

Section: Discussionmentioning

confidence: 99%

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Light-Induced Reactivity Switch at O₂–Activating Bioinspired Copper(I) Complexes

Diao,

Baidiuk,

Chaussy

et al. 2024

JACS Au

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Using light to unveil unexplored reactivities of earth-abundant metal–oxygen intermediates is a formidable challenge, given the already remarkable oxidation ability of these species in the ground state. However, the light-induced reactivity of Cu–O2 intermediates still remains unexplored, due to the photoejection of O2 under irradiation. Herein, we describe a photoinduced reactivity switch of bioinspired O2-activating CuI complexes, based on the archetypal tris(2-pyridyl-methyl)amine (TPA) ligand. This report represents a key precedent for light-induced reactivity switch in Cu–O2 chemistry, obtained by positioning C–H substrates in close proximity of the active site. Open and caged CuI complexes displaying an internal aryl ether substrate were evaluated. Under light, a Cu–O2 mediated reaction takes place that induces a selective conversion of the internal aryl ether unit to a phenolate-CH2– moiety with excellent yields. This light-induced transformation displays high selectivity and allows easy postfunctionalization of TPA-based ligands for straightforward preparation of challenging heteroleptic structures. In the absence of light, O2 activation results in the standard oxidative cleavage of the covalently attached substrate. A reaction mechanism that supports a monomeric cupric-superoxide-dependent reactivity promoted by light is proposed on the basis of reactivity studies combined with (TD-) DFT calculations.

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Section: Discussionmentioning

confidence: 99%

“…In particular, aryl ether linkages are important targets found in numerous biomolecules as lignin. 57 Future work in our laboratory will be devoted to the transfer of this reactivity toward external substrates.…”

Section: Discussionmentioning

confidence: 99%

Light-Induced Reactivity Switch at O₂–Activating Bioinspired Copper(I) Complexes

Diao,

Baidiuk,

Chaussy

et al. 2024

JACS Au

View full text Add to dashboard Cite

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“…Furthermore, as the functional group density and diversity increase with increasing molecular complexity, the prospect of catalyst intolerance of a specific functional group within the target molecule may limit applicability . If the selected substrate for functionalization possesses units with strongly coordinating groups these can compete for catalyst binding, and either partially or completely inhibit the desired reactivity by competitive catalyst coordination or complete sequestration. − Robustness screening of a wide selection of additive reagents added into optimized reaction procedures using simple substrates has allowed for elucidation of inhibitory and intolerable functional groups within established procedures and thus has served as a guide before the application to high-value complex molecules is attempted …”

Section: Introductionmentioning

confidence: 99%

Transition-Metal-Catalyzed C–H Bond Activation for the Formation of C–C Bonds in Complex Molecules

et al. 2023

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Site-predictable and chemoselective C–H bond functionalization reactions offer synthetically powerful strategies for the step-economic diversification of both feedstock and fine chemicals. Many transition-metal-catalyzed methods have emerged for the selective activation and functionalization of C–H bonds. However, challenges of regio- and chemoselectivity have emerged with application to highly complex molecules bearing significant functional group density and diversity. As molecular complexity increases within molecular structures the risks of catalyst intolerance and limited applicability grow with the number of functional groups and potentially Lewis basic heteroatoms. Given the abundance of C–H bonds within highly complex and already diversified molecules such as pharmaceuticals, natural products, and materials, design and selection of reaction conditions and tolerant catalysts has proved critical for successful direct functionalization. As such, innovations within transition-metal-catalyzed C–H bond functionalization for the direct formation of carbon–carbon bonds have been discovered and developed to overcome these challenges and limitations. This review highlights progress made for the direct metal-catalyzed C–C bond forming reactions including alkylation, methylation, arylation, and olefination of C–H bonds within complex targets.

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Sequential Cleavage of Lignin Systems by Nitrogen Monoxide and Hydrazine

Hofmann¹,

Hofmann²,

Prusko³

et al. 2020

Adv Synth Catal

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The cleavage of representative lignin systems has been achieved in a metal‐free two‐step sequence first employing nitrogen monoxide for oxidation followed by hydrazine for reductive C−O bond scission. In combining nitrogen monoxide and lignin, the newly developed valorization strategy shows the particular feature of starting from two waste materials, and it further exploits the attractive conditions of a Wolff‐Kishner reduction for C−O bond cleavage for the first time.

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Origins of Catalyst Inhibition in the Manganese‐Catalysed Oxidation of Lignin Model Compounds with H₂O₂

Cited by 10 publications

References 58 publications

Light-Induced Reactivity Switch at O₂–Activating Bioinspired Copper(I) Complexes

Light-Induced Reactivity Switch at O₂–Activating Bioinspired Copper(I) Complexes

Transition-Metal-Catalyzed C–H Bond Activation for the Formation of C–C Bonds in Complex Molecules

Sequential Cleavage of Lignin Systems by Nitrogen Monoxide and Hydrazine

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Origins of Catalyst Inhibition in the Manganese‐Catalysed Oxidation of Lignin Model Compounds with H2O2

Cited by 10 publications

References 58 publications

Light-Induced Reactivity Switch at O2–Activating Bioinspired Copper(I) Complexes

Light-Induced Reactivity Switch at O2–Activating Bioinspired Copper(I) Complexes

Transition-Metal-Catalyzed C–H Bond Activation for the Formation of C–C Bonds in Complex Molecules

Sequential Cleavage of Lignin Systems by Nitrogen Monoxide and Hydrazine

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Product

Resources

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Origins of Catalyst Inhibition in the Manganese‐Catalysed Oxidation of Lignin Model Compounds with H₂O₂

Light-Induced Reactivity Switch at O₂–Activating Bioinspired Copper(I) Complexes

Light-Induced Reactivity Switch at O₂–Activating Bioinspired Copper(I) Complexes