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Hota PK, Jose A, Panda S, Dunietz EM, Herzog AE, Wojcik L, Le Poul N, Belle C, Solomon EI, Karlin KD. Coordination Variations within Binuclear Copper Dioxygen-Derived (Hydro)Peroxo and Superoxo Species; Influences upon Thermodynamic and Electronic Properties. J Am Chem Soc 2024; 146:13066-13082. [PMID: 38688016 PMCID: PMC11161030 DOI: 10.1021/jacs.3c14422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
Copper ion is a versatile and ubiquitous facilitator of redox chemical and biochemical processes. These include the binding of molecular oxygen to copper(I) complexes where it undergoes stepwise reduction-protonation. A detailed understanding of thermodynamic relationships between such reduced/protonated states is key to elucidate the fundamentals of the chemical/biochemical processes involved. The dicopper(I) complex [CuI2(BPMPO-)]1+ {BPMPOH = 2,6-bis{[(bis(2-pyridylmethyl)amino]methyl}-4-methylphenol)} undergoes cryogenic dioxygen addition; further manipulations in 2-methyltetrahydrofuran generate dicopper(II) peroxo [CuII2(BPMPO-)(O22-)]1+, hydroperoxo [CuII2(BPMPO-)(-OOH)]2+, and superoxo [CuII2(BPMPO-)(O2•-)]2+ species, characterized by UV-vis, resonance Raman and electron paramagnetic resonance (EPR) spectroscopies, and cold spray ionization mass spectrometry. An unexpected EPR spectrum for [CuII2(BPMPO-)(O2•-)]2+ is explained by the analysis of its exchange-coupled three-spin frustrated system and DFT calculations. A redox equilibrium, [CuII2(BPMPO-)(O22-)]1+ ⇄ [CuII2(BPMPO-)(O2•-)]2+, is established utilizing Me8Fc+/Cr(η6-C6H6)2, allowing for [CuII2(BPMPO-)(O2•-)]2+/[CuII2(BPMPO-)(O22-)]1+ reduction potential calculation, E°' = -0.44 ± 0.01 V vs Fc+/0, also confirmed by cryoelectrochemical measurements (E°' = -0.40 ± 0.01 V). 2,6-Lutidinium triflate addition to [CuII2(BPMPO-)(O22-)]1+ produces [CuII2(BPMPO-)(-OOH)]2+; using a phosphazene base, an acid-base equilibrium was achieved, pKa = 22.3 ± 0.7 for [CuII2(BPMPO-)(-OOH)]2+. The BDFEOO-H = 80.3 ± 1.2 kcal/mol, as calculated for [CuII2(BPMPO-)(-OOH)]2+; this is further substantiated by H atom abstraction from O-H substrates by [CuII2(BPMPO-)(O2•-)]2+ forming [CuII2(BPMPO-)(-OOH)]2+. In comparison to known analogues, the thermodynamic and spectroscopic properties of [CuII2(BPMPO-)] O2-derived adducts can be accounted for based on chelate ring size variations built into the BPMPO- framework and the resulting enhanced CuII-ion Lewis acidity.
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Affiliation(s)
- Pradip Kumar Hota
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Anex Jose
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Sanjib Panda
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Eleanor M Dunietz
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Austin E Herzog
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Laurianne Wojcik
- UMR CNRS 6521, Université de Bretagne Occidentale, 6 Avenue Le Gorgeu, CS 93837, Brest Cedex 3 29238, France
| | - Nicolas Le Poul
- UMR CNRS 6521, Université de Bretagne Occidentale, 6 Avenue Le Gorgeu, CS 93837, Brest Cedex 3 29238, France
| | - Catherine Belle
- Université Grenoble-Alpes, CNRS, DCM, UMR 5250, Grenoble 38058, France
| | - Edward I Solomon
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Kenneth D Karlin
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
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Tsuda M, Morita T, Morita Y, Takaya J, Nakamura H. Methylene Insertion into Nitrogen-Heteroatom Single Bonds of 1,2-Azoles via a Zinc Carbenoid: An Alternative Tool for Skeletal Editing. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2307563. [PMID: 38148471 PMCID: PMC10933618 DOI: 10.1002/advs.202307563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 12/10/2023] [Indexed: 12/28/2023]
Abstract
The nitrogen-heteroatom single bonds of 1,2-azoles and isoxazolines underwent methylene insertion in the presence of CH2 I2 (6 equiv.) and diethylzinc (3 equiv.) to produce a wide variety of the ring-expanded six-membered heterocycles. Density functional theory calculations suggest that the methylene insertion proceeds via cleavage of nitrogen-heteroatom single bonds followed by ring closure.
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Affiliation(s)
- Masato Tsuda
- School of Life Science and TechnologyTokyo Institute of Technology4259 Nagatsuta‐cho Midori‐kuYokohama226–8501Japan
| | - Taiki Morita
- School of Life Science and TechnologyTokyo Institute of Technology4259 Nagatsuta‐cho Midori‐kuYokohama226–8501Japan
- Laboratory for Chemistry and Life ScienceInstitute of Innovative ResearchTokyo Institute of Technology4259 Nagatsuta‐cho Midori‐kuYokohama226–8501Japan
| | - Yuto Morita
- Department of ChemistrySchool of ScienceTokyo Institute of TechnologyO‐okayamaMeguro‐kuTokyo152–8551Japan
| | - Jun Takaya
- Department of ChemistrySchool of ScienceTokyo Institute of TechnologyO‐okayamaMeguro‐kuTokyo152–8551Japan
| | - Hiroyuki Nakamura
- School of Life Science and TechnologyTokyo Institute of Technology4259 Nagatsuta‐cho Midori‐kuYokohama226–8501Japan
- Laboratory for Chemistry and Life ScienceInstitute of Innovative ResearchTokyo Institute of Technology4259 Nagatsuta‐cho Midori‐kuYokohama226–8501Japan
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Zhang S, Goswami S, Schulz KHG, Gill K, Yin X, Hwang J, Wiese J, Jaffer I, Gil RR, Garcia-Bosch I. Regioselective Hydroxylation of Unsymmetrical Ketones Using Cu, H 2O 2, and Imine Directing Groups via Formation of an Electrophilic Cupric Hydroperoxide Core. J Org Chem 2024; 89:2622-2636. [PMID: 38324058 PMCID: PMC10877615 DOI: 10.1021/acs.joc.3c02647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 01/16/2024] [Accepted: 01/23/2024] [Indexed: 02/08/2024]
Abstract
Herein, we describe the regioselective functionalization of unsymmetrical ketones using imine directing groups, Cu, and H2O2. The C-H hydroxylation of the substrate-ligands derived from 2-substituted benzophenones occurred exclusively at the γ-position of the unsubstituted ring due to the formation of only one imine stereoisomer. Conversely, the imines derived from 4-substituted benzophenones produced E/Z mixtures that upon reacting with Cu and H2O2 led to two γ-C-H hydroxylation products. Contrary to our initial hypothesis, the ratio of the hydroxylation products did not depend on the ratio of the E/Z isomers but on the electrophilicity of the reactive [LCuOOH]1+. A detailed mechanistic analysis suggests a fast isomerization of the imine substrate-ligand binding the CuOOH core before the rate-determining electrophilic aromatic hydroxylation. Varying the benzophenone substituents and/or introducing electron-donating and electron-withdrawing groups on the 4-position of pyridine of the directing group allowed for fine-tuning of the electrophilicity of the mononuclear [LCuOOH]1+ to reach remarkable regioselectivities (up to 91:9 favoring the hydroxylation of the electron-rich arene ring). Lastly, we performed the C-H hydroxylation of alkyl aryl ketones, and like in the unsymmetrical benzophenones, the regioselectivity of the transformations (sp3 vs sp2) could be controlled by varying the electronics of the substrate and/or the directing group.
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Affiliation(s)
- Shuming Zhang
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Sunipa Goswami
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Karl H. G. Schulz
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Karan Gill
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Xinyi Yin
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Jimin Hwang
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Jasmine Wiese
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Isabel Jaffer
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Roberto R. Gil
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Isaac Garcia-Bosch
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
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Fan X, Li S, Wang C, Deng Y, Zhang C, Wang Z. Research on Fluoropyridine-based Benzoxazine with High Thermal Stability and Excellent Flame Retardancy for its Application in Coatings. Eur Polym J 2023. [DOI: 10.1016/j.eurpolymj.2023.111884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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