Selective benzylic C–C coupling catalyzed by a bioinspired dicopper complex

Prokofieva, Angelina; Prikhod'ko, Alexander I.; Dechert, Sebastian; Meyer, Franc

doi:10.1039/b718162k

Cited by 32 publications

(16 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…A significant part of the motivation for studying biological systems stems from the desire to utilize the knowledge gained to achieve chemistry of a synthetically useful and novel nature. Binuclear copper(II) complexes employing a bioinspired pyrazole‐based ligand system have shown the potential to function in such a capacity, for example by mediating both benzylic and phenylic C–C coupling reactions 129,130. The pyrazole unit has also proven useful in condensing the features of two mononuclear metallobiosites into a discrete binucleating scaffold.…”

Section: Discussionmentioning

confidence: 99%

Modelling Binuclear Metallobiosites: Insights from Pyrazole‐Supported Biomimetic and Bioinspired Complexes

Dalle

Meyer

2015

Eur J Inorg Chem

Self Cite

View full text Add to dashboard Cite

The development of a new route to α‐aminoboronates using an iridium‐catalyzed allylic amination on boronated substrates is described. Unlike the boronate group, the trifluoroborato substituent was found to govern the regioselectivity exclusively in favor of branched products. The transformation of an allylic substitution product into an α‐aminoboronic ester in an efficient way validated the implementation of this approach.

show abstract

Section: Discussionmentioning

confidence: 99%

Modelling Binuclear Metallobiosites: Insights from Pyrazole‐Supported Biomimetic and Bioinspired Complexes

Dalle

Meyer

2015

Eur J Inorg Chem

Self Cite

View full text Add to dashboard Cite

show abstract

“…In the absence of oxygen only the stilbenequinone and unreacted starting material are obtained, suggesting that the oxidation of the initial coupling product occurs rapidly. A bioinspired binuclear copper complex 1046 and a copper-urea oligomer have been shown to effect the same transformation in lower yield. 698 …”

Section: Reactions Of Phenols and Naphtholsmentioning

confidence: 99%

Aerobic Copper-Catalyzed Organic Reactions

et al. 2013

View full text Add to dashboard Cite

24 peroxide [Cu I (pyr)(tpb)] 10 mol % TBHP, 1 atm O 2 , 1:2 AcOH/pyr, rt, 24 h ∼2.5 26 74 g 35 25 n-hexane aldehyde CuCl 2 , 18-crown-6 1 atm O 2 , MeCHO, CH 2 Cl 2 , 70 °C, 24 h 2.4 91 h 9 34a 26 n-decane aldehyde Cu II Cl 16 Pc-AM(PS) 3 equiv of PhCHO, MeCN, 1 atm O 2 , 50 °C 15.4 100 i 61 a See Chart 2 for ligand structures. b Also 28% cyclohexene. c Also 26% cyclohexene. d Mixture of alcohol and hydroperoxide. e Remainder of product is cyclohexene. f Approximately 93:7 of 1-adamantol/2-adamantol. g Approximately 98:2 of 1-adamantol/2-adamantol. h Afforded oxidation products in an approximately 1:1 ratio at the 2-and 3-positions. i Mixture of decanones.

show abstract

“…[25] Taking into consideration that most dicopper enzymes contain elements of asymmetry in their active site that make the two copper sites inequivalent, and speculating that this aspect could introduce additional factors that mediate the inherent reactivity of the site, we have been interested in studying O 2 -activation reactions mediated by unsymmetric dicopper complexes. Phenolic molecules were envisioned as interesting substrate probes because their oxidation has technological relevance, [27][28][29] and is a very common reaction in a myriad of enzymatic systems. Two basic oxidative transformations are commonly found for this type of substrate; homolytic breakage of the O À H bond, and oxidation of the aromatic ring.…”

Section: )A C H T U N G T R E N N U N G (P-x-pho)(m-xyl N3n4 )]mentioning

confidence: 99%

Electrophilic Arene Hydroxylation and Phenol OH Oxidations Performed by an Unsymmetric μ‐η¹:η¹‐O₂‐Peroxo Dicopper(II) Complex

Garcia‐Bosch

Ribas

Costas

2012

Chemistry A European J

View full text Add to dashboard Cite

Reactions of the unsymmetric dicopper(II) peroxide complex [Cu(II)(2)(μ-η(1):η(1)-O(2))(m-XYL(N3N4))](2+) (1 O(2), where m-XYL is a heptadentate N-based ligand), with phenolates and phenols are described. Complex 1 O(2) reacts with p-X-PhONa (X = MeO, Cl, H, or Me) at -90 °C performing tyrosinase-like ortho-hydroxylation of the aromatic ring to afford the corresponding catechol products. Mechanistic studies demonstrate that reactions occur through initial reversible formation of metastable association complexes [Cu(II)(2)(μ-η(1):η(1)-O(2))(p-X-PhO)(m-XYL(N3N4))](+) (1 O(2)⋅X-PhO) that then undergo ortho-hydroxylation of the aromatic ring by the peroxide moiety. Complex 1 O(2) also reacts with 4-X-substituted phenols p-X-PhOH (X = MeO, Me, F, H, or Cl) and with 2,4-di-tert-butylphenol at -90 °C causing rapid decay of 1 O(2) and affording biphenol coupling products, which is indicative that reactions occur through formation of phenoxyl radicals that then undergo radical C-C coupling. Spectroscopic UV/Vis monitoring and kinetic analysis show that reactions take place through reversible formation of ground-state association complexes [Cu(II)(2)(μ-η(1):η(1)-O(2))(X-PhOH)(m-XYL(N3N4))](2+) (1 O(2)⋅X-PhOH) that then evolve through an irreversible rate-determining step. Mechanistic studies indicate that 1 O(2) reacts with phenols through initial phenol binding to the Cu(2)O(2) core, followed by a proton-coupled electron transfer (PCET) at the rate-determining step. Results disclosed in this work provide experimental evidence that the unsymmetric 1 O(2) complex can mediate electrophilic arene hydroxylation and PCET reactions commonly associated with electrophilic Cu(2)O(2) cores, and strongly suggest that the ability to form substrate⋅Cu(2)O(2) association complexes may provide paths to overcome the inherent reactivity of the O(2)-binding mode. This work provides experimental evidence that the presence of a H(+) completely determines the fate of the association complex [Cu(II)(2)(μ-η(1):η(1)-O(2))(X-PhO(H))(m-XYL(N3N4))](n+) between a PCET and an arene hydroxylation reaction, and may provide clues to help understand enzymatic reactions at dicopper sites.

show abstract

Selective benzylic C–C coupling catalyzed by a bioinspired dicopper complex

Abstract: A highly preorganized bioinspired dicopper complex with imidazole ligation catalyzes the selective benzylic para-C-H activation of 2,4,6-trimethylphenol under aerobic conditions, yielding either the stilbenequinone or 4-methoxymethyl-2,6-dimethylphenol depending on the solvent used.

Cited by 32 publications

References 19 publications

Modelling Binuclear Metallobiosites: Insights from Pyrazole‐Supported Biomimetic and Bioinspired Complexes

Modelling Binuclear Metallobiosites: Insights from Pyrazole‐Supported Biomimetic and Bioinspired Complexes

Aerobic Copper-Catalyzed Organic Reactions

Electrophilic Arene Hydroxylation and Phenol OH Oxidations Performed by an Unsymmetric μ‐η¹:η¹‐O₂‐Peroxo Dicopper(II) Complex

Contact Info

Product

Resources

About

Selective benzylic C–C coupling catalyzed by a bioinspired dicopper complex

Abstract: A highly preorganized bioinspired dicopper complex with imidazole ligation catalyzes the selective benzylic para-C-H activation of 2,4,6-trimethylphenol under aerobic conditions, yielding either the stilbenequinone or 4-methoxymethyl-2,6-dimethylphenol depending on the solvent used.

Cited by 32 publications

References 19 publications

Modelling Binuclear Metallobiosites: Insights from Pyrazole‐Supported Biomimetic and Bioinspired Complexes

Modelling Binuclear Metallobiosites: Insights from Pyrazole‐Supported Biomimetic and Bioinspired Complexes

Aerobic Copper-Catalyzed Organic Reactions

Electrophilic Arene Hydroxylation and Phenol OH Oxidations Performed by an Unsymmetric μ‐η1:η1‐O2‐Peroxo Dicopper(II) Complex

Contact Info

Product

Resources

About

Electrophilic Arene Hydroxylation and Phenol OH Oxidations Performed by an Unsymmetric μ‐η¹:η¹‐O₂‐Peroxo Dicopper(II) Complex