Radical ions in photochemistry.  I.  1,1-Diphenylethylene cation radical

Neunteufel, R. A.; Arnold, Donald R.

doi:10.1021/ja00793a060

Cited by 184 publications

(72 citation statements)

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“…In addition, we obtained traces of methoxycyclooctane from irradiations of p-benzoquinone and cyclooctene in methanol or acetonitrile/methanol. This product represents entrapment of a cyclooctene radical cation by methanol, and is analogous to the alcohol/ alkene adducts obtained by Neunteufel and Arnold (24) in reactions sensitized by methyl benzoates. In our studies, however, the quantity of the methanol adduct was always very small.…”

Section: Possibility Of Exciplex Intermediatessupporting

confidence: 61%

On the Mechanism of Oxetan Formation in the Photocycloaddition of p-Benzoquinone to Alkenes

Bunce¹,

Hadley²

1975

Can. J. Chem.

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Section: Possibility Of Exciplex Intermediatessupporting

confidence: 61%

On the Mechanism of Oxetan Formation in the Photocycloaddition of p-Benzoquinone to Alkenes

Bunce¹,

Hadley²

1975

Can. J. Chem.

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“…The effects of variation in structure and the effects of substitution by electron-donating and electron-withdrawing groups must be understood, for each step of the reaction mechScheme 1. The mechanism for the photosensitized (electron transfer) nucleophilic (methanol) addition to arylalkenes (reaction [I]) (3). hv Scheme 2.…”

Section: Trans Cismentioning

confidence: 99%

“…The mechanism for the photosensitized (electron transfer) isomerization involves deprotonation of the radical cation, reduction of the resulting radical, and reprotonation of the anion (reaction [3]) (5).…”

Section: Trans Cismentioning

confidence: 99%

“…Three reactions that are of particular interest to us are (i) the addition of nucleophiles to the radical cation of arylalkenes, a reaction that can yield the anti-Markovnikov addition product; (ii) the c a r b o n~a r b o n bond cleavage of radical cations, which ultimately yields products derived from the radical and carbocation fragments; (iii) the deprotonation of the radical cation, a reaction that can be used to invert the configuration at a saturated carbon centre. Archetypical examples of these processes are illustrated in reactions [I]- [3] (3)(4)(5). Reoction [ 2 ] (4) Reoction [3] (5) h v , A…”

Section: Introductionmentioning

confidence: 99%

“…Archetypical examples of these processes are illustrated in reactions [I]- [3] (3)(4)(5). Reoction [ 2 ] (4) Reoction [3] (5) h v , A…”

Section: Introductionmentioning

confidence: 99%

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The effect of meta- or para-cyano substitution on the reactivity of the radical cations of arylalkenes and alkanes. Radical ions in photochemistry, Part 34

Arnold¹,

Du²,

Chen³

1995

Can. J. Chem.

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The effect of electron-withdrawing substituents, mera-orpnr~l-cyano, on the rcactivity of the radical cation of arylalkenes and alkanes has been determined. The radical cations were generated by single electron transfer (set) to an electron-accepting photosensitizer. Three reactions were studied: (i) the addition of nucleophile to the radical cation of arylalkenes, (ii) cleavage of the benzylic carbon-carbon bond of the radical cation of arylalkanes; and (iii) the deprotonation of the benzylic carbon-hydrogen bond of the radical cation of arylalkanes. The radical cations of 4-(1-pheny1ethenyl)benzonitrile (lb), 3-(1-phenylethenyl)benzonitrile (lc), 4-(2-methoxy-I-phenylethy1)benzonitrile (20). 3-(2-methoxy-I-phenylethy1)benzonitrile ( 2~) .cis-and tr.crrls-5-cyano-2-methoxy-1-phenylindane (60-cis and -rratls), and 6-cyano-3-phenylindene (7B) were generated, by single electron transfer to the lowest excited singlet state of 1,4-dicyanobenzene (3), in acetonitrile-methanol. The radical cations of lb, lc, and 70 react with methanol to yield the nrzri-Markovnikov adducts (20,2c, and 60-cis and 60-rmns). The radical cations of 2 0 . 2~. and 60-rrcrrzs cleave at the benzylic carbonsarbon bond to give products derived from the radical and carbocation fragments. The radical cation of 60-cis deprotonates from the benzylic position with subsequent formation of the diastereomer, 60-rrarls. This behaviour can be explained1 predicted on the basis of the proposed mechanisms for these reactions. Molecular orbital calculations (AM 1) support the conclusions.Key words: photosensitized, electron transfer, radical ions, radicals, molecular orbital calculations (AMI).RCsumC : On a dCterminC I'effet de substituants Clectroattracteur, les groupes rrle'ra-et pcrrcr-cyano, sur la rCactivitC de cations radicaux d'arylalcknes et alcanes. On a gCnCrC les cations radicaux par le transfert d'un seul Clectron i un photosensibilisateur accepteur d'klectron. On a CtudiC trois rCactions : (i) l'addition d'un nuclCophile sur le cation radical des arylalcknes; (ii) le clivage de la liaison carbone-carbone benzylique du cation radical des arylalcanes et (iii) la dCprotonation de la liaison carbone-hydrogkne benzylique du cation radical des arylalcanes. On a gCnCrC les cations radicaux des 4-(1-phCnylCthCny1)benzonitrile (10). 3-(1-phCnylCthCny1)-benzonitrile (lc), 4-(2-mCthoxy-1-phCny1Cthyl)benzonitrile (20). 3-(2-mCthoxy-I-phCnylCthy1)benzonitrile (2c), cis-et r,nr1~-5-cyan0-2-mCthoxy-I -phCnylindane (6b-cis et -fmrls) et 6-cyano-3-phCnylindkne (70) par un transfert d'un seul Clectron j. l'Ctat singulet excite le plus bas du 1,4-dicyanobenzkne (3), en solution dans l'acCtonitrile-mCthano1. Les cations radicaux des composCs lb, l c et 70 rkagissent avec le methanol pour donner des adduits arlri-Markovnikov (2b, 2c et 60-cis et 60-rrarls). Les radicaux cations 2 0 . 2~ et 60-rrans se clivent au niveau de la liaison carbone-carbone benzylique pour donner des produits dCrivCs des fragments radicalaires et carbocationiques. Le cation radica...

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Regio- and Stereoselective Cyclization Reactions of Unsaturated Silyl Enol Ethers by Photoinduced Electron Transfer – Mechanistic Aspects and Synthetic Approach

Hintz

Mattay²,

Eldik

et al. 1998

Eur. J. Org. Chem.

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Radical ions in photochemistry. I. 1,1-Diphenylethylene cation radical

Cited by 184 publications

References 0 publications

On the Mechanism of Oxetan Formation in the Photocycloaddition of p-Benzoquinone to Alkenes

On the Mechanism of Oxetan Formation in the Photocycloaddition of p-Benzoquinone to Alkenes

The effect of meta- or para-cyano substitution on the reactivity of the radical cations of arylalkenes and alkanes. Radical ions in photochemistry, Part 34

Regio- and Stereoselective Cyclization Reactions of Unsaturated Silyl Enol Ethers by Photoinduced Electron Transfer – Mechanistic Aspects and Synthetic Approach

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