Photoredox Reactions of Quinones

Ando, Yoshio; Suzuki, Keisuke

doi:10.1002/chem.201801064

Cited by 42 publications

(19 citation statements)

References 74 publications

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“…In this review, we aim to highlight recent applications of carbonyl compounds in metal‐free photochemical reactions. Initially, we will briefly cover fundamental aspects and the reactivity of photoexcited ketones, 1,2‐diketones, xanthones and quinones . This reactivity is crucial for the understanding of the mechanistic scenarios described along the text and therefore will be timely highlighted when necessary.…”

Section: Introductionmentioning

confidence: 99%

Photochemistry of Carbonyl Compounds: Application in Metal‐Free Reactions

et al. 2019

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Synthetic organic photochemistry is an efficient and environmentally friendly alternative to assemble biologically and chemically relevant scaffolds. The photon energy allows access to reactive intermediates by using a clean energy source under mild conditions. Moreover, sustainable synthesis can be achieved by using metal-free photochemistry. In this review, the photochemistry of carbonyl compounds and their application as reagents, catalysts or promoters of metal-free photochemical transformations are discussed. Fundamental aspects and reactivity of the carbonyl compounds are briefly presented in the introduction section, followed by recent applications of carbonyl compounds in photochemical reactions. The text is organized according to the role of the carbonyl compounds in the process. First, approaches in which carbonyl compounds are employed in stoichiometric or super-stoichiometric amounts (as reaction substrates or photoinitiators) are described. Thereafter, their application as photocatalysts and photosensitizers are discussed and mechanistic studies are comprehensively presented.

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Section: Introductionmentioning

confidence: 99%

Photochemistry of Carbonyl Compounds: Application in Metal‐Free Reactions

et al. 2019

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“…Redox properties of quinone compounds have been well documented in the literature . For the Ru–QC complexes, the reduction waves in their cyclic voltammograms (e.g., Figure ) attributable to a QC-based process could account for their HAT reactivity with C–H and X–H substrates.…”

Section: Discussionmentioning

confidence: 81%

Ruthenium(II) Porphyrin Quinoid Carbene Complexes: Synthesis, Crystal Structure, and Reactivity toward Carbene Transfer and Hydrogen Atom Transfer Reactions

Wang

Wan

et al. 2019

J. Am. Chem. Soc.

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Reactivity study of novel metal carbene complexes can offer new opportunities in catalytic carbene transfer reactions as well as in other synthetic protocols. Metal complexes with quinoid carbene (QC) ligands are assumed to be key intermediates in a variety of metal-catalyzed QC transfer reactions using diazo quinones, which demands development of the chemistry of QC transfer of well characterized metal–QC complexes. Herein we report the isolation and QC transfer of ruthenium porphyrins [Ru(Por)(QC)] which contribute the first examples of (i) structurally characterized metal–QC complex (by X-ray crystallography) and (ii) isolated metal–QC complex that undergoes QC transfer reaction. The complexes [Ru(Por)(QC)] were prepared from reaction of [Ru(Por)(CO)] with diazo quinones and exhibited dual reactivity, i.e., hydrogen atom transfer (HAT) as well as QC transfer. The stoichiometric QC transfer reactions from these Ru–QC complexes to nitrosoarenes (ArNO) afforded nitrones in up to 90% yield, and the corresponding catalytic reactions were also developed. Both the stoichiometric and catalytic reactions for a series of QC ligands bearing electron-donating and -withdrawing substituents showed a reverse substituent effect on the QC transfer reactivity. Complexes [Ru(Por)(QC)] are also reactive toward C–H and X–H (X = N, S) bonds and can catalyze aerobic oxidation of 1,4-cyclohexadiene; their stoichiometric HAT reactions with unsaturated hydrocarbons gave product yields of up to 88%. The unique dual reactivity and electronic feature of [Ru(Por)(QC)] were studied by spectroscopic means and density functional theory (DFT) calculations.

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“…A wide variety of polysubstituted benzyl radicals generated from various halides can be efficiently introduced to diversely substituted 1,4-(naphtho)quinones with good yields, thanks to a redox cycle involving the photoreduced (naphtho)quinone, oxygen, and ferric complexes. To the best of our knowledge, this is the first time that the photoreactivity of quinone is exploited for its intermolecular functionalization in a catalytic process.…”

Section: Discussionmentioning

confidence: 99%

Bioinspired Photoredox Benzylation of Quinones

2021

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3-Benzylmenadiones were obtained in good yields by using a blue light-induced photoredox process in the presence of Fe(III), oxygen and γ-terpinene acting as a HAT agent. This methodology is compatible with a wide variety of diversely substituted 1,4-naphthoquinones as well as various cheap, readily available benzyl bromides with excellent functional group tolerance. The benzylation mechanism was investigated and supports a three-step radical cascade with the key involvement of photogenerated superoxide anion radical.

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Photoredox Reactions of Quinones

Cited by 42 publications

References 74 publications

Photochemistry of Carbonyl Compounds: Application in Metal‐Free Reactions

Photochemistry of Carbonyl Compounds: Application in Metal‐Free Reactions

Ruthenium(II) Porphyrin Quinoid Carbene Complexes: Synthesis, Crystal Structure, and Reactivity toward Carbene Transfer and Hydrogen Atom Transfer Reactions

Bioinspired Photoredox Benzylation of Quinones

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