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Murayama S, Li Z, Liang H, Liu Y, Naka H, Maruoka K. Impact of Catalyst Deuteration on the Reactivity of Chiral Phase-Transfer Organocatalysts. Chemistry 2023; 29:e202301866. [PMID: 37332072 DOI: 10.1002/chem.202301866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 06/16/2023] [Accepted: 06/16/2023] [Indexed: 06/20/2023]
Abstract
Site-specifically deuterated organocatalysts were prepared and found to show improved reactivity over the non-deuterated analogs. Two privileged C2 -symmetric chiral binaphthyl-modified tetraalkylammonium salts were selected for this study. The stability of these phase-transfer catalysts was generally improved by site-specific deuteration, though the degree of improvement was structure dependent. In particular, a large secondary kinetic isotope effect was observed for the tetradeuterated phase-transfer catalyst. The performance of these deuterated catalysts in the asymmetric catalytic alkylation of amino acid derivatives was better than that of non-deuterated analogs at low catalyst loadings. The results suggest that catalyst deuteration is a promising strategy for enhancing the stability and performance of organocatalysts.
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Affiliation(s)
- Sei Murayama
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, 606-8501, Japan
| | - Zhurong Li
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, P. R. China
- Guangdong Provincial Key Laboratory of Plant Resources Biorefinery, Guangdong University of Technology, Guangzhou, 510006, P. R. China
| | - Huatai Liang
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, P. R. China
- Guangdong Provincial Key Laboratory of Plant Resources Biorefinery, Guangdong University of Technology, Guangzhou, 510006, P. R. China
| | - Yan Liu
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, P. R. China
- Guangdong Provincial Key Laboratory of Plant Resources Biorefinery, Guangdong University of Technology, Guangzhou, 510006, P. R. China
| | - Hiroshi Naka
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, 606-8501, Japan
- Deuterium Science Research Unit Center for the Promotion of Interdisciplinary Education and Research, Kyoto University, Kyoto, 606-8501, Japan
| | - Keiji Maruoka
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, 606-8501, Japan
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, P. R. China
- Guangdong Provincial Key Laboratory of Plant Resources Biorefinery, Guangdong University of Technology, Guangzhou, 510006, P. R. China
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Rokob TA. Pathways for Arene Oxidation in Non-Heme Diiron Enzymes: Lessons from Computational Studies on Benzoyl Coenzyme A Epoxidase. J Am Chem Soc 2016; 138:14623-14638. [PMID: 27682344 DOI: 10.1021/jacs.6b06987] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Oxygenation of aromatic rings using O2 is catalyzed by several non-heme carboxylate-bridged diiron enzymes. In order to provide a general mechanistic description for these reactions, computational studies were carried out at the ONIOM(B3LYP/BP86/Amber) level on the non-heme diiron enzyme benzoyl coenzyme A epoxidase, BoxB. The calculations revealed four possible pathways for attacking the aromatic ring: (a) electrophilic (2e-) attack by a bis(μ-oxo)-diiron(IV) species (Q pathway); (b) electrophilic (2e-) attack via the σ* orbital of a μ-η2:η2-peroxo-diiron(III) intermediate (Pσ* pathway); (c) radical (1e-) attack via the π*-orbital of a superoxo-diiron(II,III) species (Pπ* pathway); (d) radical (1e-) attack of a partially quenched bis(μ-oxo)-diiron(IV) intermediate (Q' pathway). The results allowed earlier work of de Visser on olefin epoxidation by diiron complexes and QM-cluster studies of Liao and Siegbahn on BoxB to be put into a broader perspective. Parallels with epoxidation using organic peracids were also examined. Specifically for the BoxB enzyme, the Q pathway was found to be the most preferred, but the corresponding bis(μ-oxo)-diiron(IV) species is significantly destabilized and not expected to be directly observable. Epoxidation via the Pσ* pathway represents an energetically somewhat higher lying alternative; possible strategies for experimental discrimination are discussed. The selectivity toward epoxidation is shown to stem from a combination of inherent electronic properties of the thioacyl substituent and enzymatic constraints. Possible implications of the results for toluene monooxygenases are considered as well.
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Affiliation(s)
- Tibor András Rokob
- Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences , Magyar Tudósok körútja 2, 1117 Budapest, Hungary
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Poater A, Solà M. Complete σ* intramolecular aromatic hydroxylation mechanism through O2 activation by a Schiff base macrocyclic dicopper(I) complex. Beilstein J Org Chem 2013; 9:585-93. [PMID: 23616799 PMCID: PMC3628990 DOI: 10.3762/bjoc.9.63] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2012] [Accepted: 03/01/2013] [Indexed: 02/05/2023] Open
Abstract
In this work we analyze the whole molecular mechanism for intramolecular aromatic hydroxylation through O2 activation by a Schiff hexaazamacrocyclic dicopper(I) complex, [Cu(I) 2(bsH2m)](2+). Assisted by DFT calculations, we unravel the reaction pathway for the overall intramolecular aromatic hydroxylation, i.e., from the initial O2 reaction with the dicopper(I) species to first form a Cu(I)Cu(II)-superoxo species, the subsequent reaction with the second Cu(I) center to form a μ-η(2):η(2)-peroxo-Cu(II) 2 intermediate, the concerted peroxide O-O bond cleavage and C-O bond formation, followed finally by a proton transfer to an alpha aromatic carbon that immediately yields the product [Cu(II) 2(bsH2m-O)(μ-OH)](2+).
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Affiliation(s)
- Albert Poater
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, Campus de Montilivi, E-17071 Girona, Spain ; Catalan Institute for Water Research (ICRA), H2O Building, Scientific and Technological Park of the University of Girona, Emili Grahit 101, E-17003 Girona, Spain
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Dancing multiplicity states supported by a carboxylated group in dicopper structures bonded to O2. Theor Chem Acc 2013. [DOI: 10.1007/s00214-013-1336-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Noh JM, Kwak SY, Seo HS, Seo JH, Kim BG, Lee YS. Kojic acid–amino acid conjugates as tyrosinase inhibitors. Bioorg Med Chem Lett 2009; 19:5586-9. [DOI: 10.1016/j.bmcl.2009.08.041] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2009] [Revised: 08/10/2009] [Accepted: 08/11/2009] [Indexed: 10/20/2022]
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Poater A. Oxidation of Copper(I) Hexaaza Macrocyclic Dinuclear Complexes. J Phys Chem A 2009; 113:9030-40. [DOI: 10.1021/jp9040716] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Albert Poater
- Modeling Lab for Nanostructures and Catalysis (MoLNaC), Dipartimento di Chimica, Università degli Studi di Salerno, via Ponte don Melillo, Fisciano (SA) 84084, Italy
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Güell M, Luis JM, Solà M, Siegbahn PEM. Theoretical study of the hydroxylation of phenolates by the Cu(2)O (2)(N,N'-dimethylethylenediamine) (2) (2+) complex. J Biol Inorg Chem 2008; 14:229-42. [PMID: 18972140 DOI: 10.1007/s00775-008-0443-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2008] [Accepted: 10/08/2008] [Indexed: 12/21/2022]
Abstract
Tyrosinase catalyzes the ortho hydroxylation of monophenols and the subsequent oxidation of the diphenolic products to the resulting quinones. In efforts to create biomimetic copper complexes that can oxidize C-H bonds, Stack and coworkers recently reported a synthetic mu-eta(2):eta(2)-peroxodicopper(II)(DBED)(2) complex (DBED is N,N'-di-tert-butylethylenediamine), which rapidly hydroxylates phenolates. A reactive intermediate consistent with a bis-mu-oxo-dicopper(III)-phenolate complex, with the O-O bond fully cleaved, is observed experimentally. Overall, the evidence for sequential O-O bond cleavage and C-O bond formation in this synthetic complex suggests an alternative mechanism to the concerted or late-stage O-O bond scission generally accepted for the phenol hydroxylation reaction performed by tyrosinase. In this work, the reaction mechanism of this peroxodicopper(II) complex was studied with hybrid density functional methods by replacing DBED in the mu-eta(2):eta(2)-peroxodicopper(II)(DBED)(2) complex by N,N'-dimethylethylenediamine ligands to reduce the computational costs. The reaction mechanism obtained is compared with the existing proposals for the catalytic ortho hydroxylation of monophenol and the subsequent oxidation of the diphenolic product to the resulting quinone with the aim of gaining some understanding about the copper-promoted oxidation processes mediated by 2:1 Cu(I)O(2)-derived species.
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Affiliation(s)
- Mireia Güell
- Departament de Química, Institut de Química Computacional, Universitat de Girona, Campus de Montilivi, 17071, Girona, Spain
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