Photocatalytic Formation of Dimethyllepidopterene from 9,10-Dimethylanthracene via Electron-Transfer Oxidation

Ohkubo, Kei; Iwata, Ryosuke; Miyazaki, Soushi; Kojima, Takahiko; Fukuzumi, Shunichi

doi:10.1021/ol062554y

Cited by 27 publications

(32 citation statements)

References 38 publications

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“…The complex multi-fused-ring structure dimethyllepidopterene 106.2 was discovered to form under the photoredox activity of MesAcr-Me + from the simple starting material 9,10-dimethylanthracene 106.1 (Scheme 106). 395 The stepwise mechanism likely first involves removal of a benzylic hydrogen, seeing as addition of tetrabutylammonium hydroxide led to increased yield, 176 Substituents on both the activated alkynyl coupling partner 107.1 and the azirine 107.2 were varied, providing diverse, unsymmetrically substituted pyrroles in wide-ranging yields. Consistent with the earlier proposal by Muller and Mattay, azaallenyl cation radical 107.9 participates in a stepwise cyclization with alkyne 107.1, first forming distonic cation radical 107.10 by radical addition.…”

Section: Alkene Hydrofunctionalizationmentioning

confidence: 99%

Organic Photoredox Catalysis

2016

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In this review, we highlight the use of organic photoredox catalysts in a myriad of synthetic transformations with a range of applications. This overview is arranged by catalyst class where the photophysics and electrochemical characteristics of each is discussed to underscore the differences and advantages to each type of single electron redox agent. We highlight both net reductive and oxidative as well as redox neutral transformations that can be accomplished using purely organic photoredox-active catalysts. An overview of the basic photophysics and electron transfer theory is presented in order to provide a comprehensive guide for employing this class of catalysts in photoredox manifolds.

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Section: Alkene Hydrofunctionalizationmentioning

confidence: 99%

Organic Photoredox Catalysis

2016

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“…The electron-transfer state of a simple donor-acceptor linked dyad, 9mesityl-10-methylacridnium ion (Acr + -Mes), produced upon photoirradiation can oxidize and reduce external electron donors Scheme 12 Photocatalytic formation of dimethyllepidopterene with Acr + -Mes. 127 and acceptors to produce the corresponding radical cations and radical anions, respectively. Much smaller concentrations of substrates can be used for the oxidation because of the long lifetime of the electron-transfer state (Acr • -Mes •+ ) as compared with the use of the singlet excited state of AcrH + and AcrPh + .…”

Section: Discussionmentioning

confidence: 99%

Selective photocatalytic reactions with organic photocatalysts

2013

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Selective photocatalytic oxygenation of various substrates has been achieved using organic photocatalysts via photoinduced electron-transfer reactions of photocatalysts with substrates and dioxygen under visible light irradiation. Photoinduced electron transfer from benzene to the singlet-excited state of the 3-cyano-1-methylquinolinium ion has enabled the oxidation of benzene by dioxygen with water to yield phenol selectively. Alkoxybenzenes were obtained when water was replaced by alcohols under otherwise the same experimental conditions. Photocatalytic selective oxygenation reactions of aromatic compounds have also been achieved using an electron donor-acceptor linked dyad, 9-mesityl-10-methylacridinium ion (Acr + -Mes) acting as a photocatalyst and dioxygen as an oxidant under visible light irradiation. The oxygenation reaction is initiated by intramolecular photoinduced electron transfer from the mesitylene moiety to the singlet-excited state of the acridinium moiety of Acr + -Mes to afford an extremely longlived electron-transfer state. The electron-transfer state can oxidize and reduce substrates and dioxygen, respectively, leading to selective oxygenation and halogenation of substrates. C-C bond formation of substrates has also been made possible by using Acr + -Mes as a photocatalyst.

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“…Although the photoexcitation of anthracene gives a [4 + 4] dimer through the singlet excimer intermediate, 110,111 another type of anthracene dimer derivative, i.e., dimethyllepidopterene (5,6,11,12-tetrahydro-4b,12[1′,2′],6,10b[1″,2″]-dibenzenochrysene) has been prepared by the photocatalytic carboncarbon bond formation of 9,10-dimethylanthracene (DMA) in chloroform via the electron-transfer oxidation of DMA with the ET state of Acr + -Mes (Scheme 15). 112 Visible-light irradiation (λ > 430 nm) of the absorption band of Acr + -Mes (5.0 × 10 −4 M) in a de-aerated chloroform (CDCl 3 ) solution containing DMA (1.5 × 10 −3 M) results in the formation of dimethyllepidopterene, 1,2-bis(9-anthracenyl)ethane, and 9-(β,β-dichloroethyl)-10-methylanthracene (Scheme 15). 112 The isolated yield of dimethyllepidopterene was 12% after 4 h of photoirradiation at 298 K. 112 The ORTEP drawing determined from the X-ray crystal structural analysis is also shown in Scheme 15.…”

Section: Photocatalytic C-c Bond Formationmentioning

confidence: 99%

“…112 Visible-light irradiation (λ > 430 nm) of the absorption band of Acr + -Mes (5.0 × 10 −4 M) in a de-aerated chloroform (CDCl 3 ) solution containing DMA (1.5 × 10 −3 M) results in the formation of dimethyllepidopterene, 1,2-bis(9-anthracenyl)ethane, and 9-(β,β-dichloroethyl)-10-methylanthracene (Scheme 15). 112 The isolated yield of dimethyllepidopterene was 12% after 4 h of photoirradiation at 298 K. 112 The ORTEP drawing determined from the X-ray crystal structural analysis is also shown in Scheme 15. 112 The bond length of the newly formed C-C bond (C6-C6′) is 1.629 (2) Å, which is much longer than normal C-C single bonds due to the severe distortion of this compound.…”

Section: Photocatalytic C-c Bond Formationmentioning

confidence: 99%

“…• radicals dimerized to yield 1,1,2,2tetrachloroethane (CHCl 2 CHCl 2 ) or reacted with 9-methylanthrylmethyl radical to yield 9-(β,β-dichloroethyl)-10-methylanthracene (Scheme 15). 112 The deprotonation from the methyl group of DM •+ is the key step for the formation of dimethyllepidopterene. Thus, no photodimerization has occurred in the case of unsubstituted anthracene, which has no methyl group to be deprotonated, and nor in the case of 9,10-dimethylanthracene in which the deprotonation from the ethyl group may be too slow to complete with the back electron transfer.…”

Section: Photocatalytic C-c Bond Formationmentioning

confidence: 99%

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Organic synthetic transformations using organic dyes as photoredox catalysts

2014

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The oxidizing ability of organic dyes is enhanced significantly by photoexcitation. Radical cations of weak electron donors can be produced by electron transfer from the donors to the excited states of organic dyes. The radical cations thus produced undergo bond formation reactions with various nucleophiles. For example, the direct oxygenation of benzene to phenol was made possible under visible-light irradiation of 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) in an oxygen-saturated acetonitrile solution of benzene and water via electron transfer from benzene to the triplet excited state of DDQ. 3-Cyano-1-methylquinolinium ion (QuCN(+)) can also act as an efficient photocatalyst for the selective oxygenation of benzene to phenol using oxygen and water under homogeneous and ambient conditions. Alkoxybenzenes were also obtained when water was replaced by alcohol under otherwise identical experimental conditions. QuCN(+) can also be an effective photocatalyst for the fluorination of benzene with O2 and fluoride anion. Photocatalytic selective oxygenation of aromatic compounds was achieved using an electron donor-acceptor-linked dyad, 9-mesityl-10-methylacridinium ion (Acr(+)-Mes), as a photocatalyst and O2 as the oxidant under visible-light irradiation. The electron-transfer state of Acr(+)-Mes produced upon photoexcitation can oxidize and reduce substrates and dioxygen, respectively, leading to the selective oxygenation and halogenation of substrates. Acr(+)-Mes has been utilized as an efficient organic photoredox catalyst for many other synthetic transformations.

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Photocatalytic Formation of Dimethyllepidopterene from 9,10-Dimethylanthracene via Electron-Transfer Oxidation

Cited by 27 publications

References 38 publications

Organic Photoredox Catalysis

Organic Photoredox Catalysis

Selective photocatalytic reactions with organic photocatalysts

Organic synthetic transformations using organic dyes as photoredox catalysts

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