Radical ions in photochemistry. 5. Photosensitized (electron transfer) cyanation of olefins

Maroulis, A. J.; Shigemitsu, Yasuo; Arnold, Donald R.

doi:10.1021/ja00470a029

Cited by 81 publications

(18 citation statements)

References 2 publications

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“…Arnold also developed olefin anti-Markovnikov hydrocyanation reactions using 1-cyanonaphthalene and a combination of KCN/18-crown-6 to afford 48% of 27.9 from 1,1-diphenylethene (27.8), though reduction product 27.10 was also isolated (eq 3, Scheme 27). 181 Though these reactions are the first anti-Markovnikov alkene hydrofunctionalization reactions promoted by photoinduced electron transfer, none of the reactions use truly catalytic loadings of the cyanoarene photooxidant.…”

Section: Oxidative Aryl−aryl Couplingmentioning

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: Oxidative Aryl−aryl Couplingmentioning

confidence: 99%

Organic Photoredox Catalysis

2016

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“…This has been noted by others (4b) and is another added benefit to the synthetic potentiality of 11. Obviously, however, photosensitization (electron transfer) by 11 cannot be used for the photocyanation of olefins (27). When the irradiation of 1,3-dicyanobenzene (6) in the presence of 2 and 11 in acetonitrile-methanol solution was first attempted, it was expected that the major product would be 38.…”

Section: Irradiation In Acetonitrile-methanolmentioning

confidence: 99%

“…However, the very low intensities of the exciplex emission rendered the determination of the emission maxima difficult. (27). 128 (38), 127 (19), 117 (27), 116 (loo), 1 I5 (46).…”

Section: Irradiation In Acetonitrile-methanolmentioning

confidence: 99%

Radical ions in photochemistry. 15. The photosubstitution reaction between dicyanobenzenes and alkyl olefins

Borg¹,

Arnold²,

Cameron³

1984

Can. J. Chem.

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Can. J. Chem. 62, (785 (1984). ' The photosubstitution (electron transfer) reaction between 1,4-dicyanobenzene (1) and 2,3-dimethyl-2-butene (2), which gives I-(4-cyanophenyl)-2,3-dimethyl-2-butene (3) and 3-(4-cyanopheny1)-2,3-dimcthyl-I-butene (4). has been extended to other dicyanobenzene-olefin mixtures. Substitution of a cyano group occurs when both 1 or 1,2-dicyanobenzene (5) are irradiated in acetonitrile solution, in the presence of 2 or cyclohexcne (16). Under comparable conditions, 1.3-dicyanobenzene (6) failed to react. Little or no substitut~on was observed in any case when the olefin was methylpropene (19). ' The results for 1 and 5 are in agreement with empirical free energy calculations (Weller equation) for the electron transfer process which, however, fail to explain the general lack of reactivity of 1,3-dicyanobenzene. Phenanthrene (11) has been shown to photosensitize the photosubstitution reaction between dicyanobenzenes and 2. Under these conditions the olefin reacts with 6 predominantly at the 4-position, resulting in overall substitution of a hydrogen atom. This reaction occurs regiospecifically, resulting in the formation of only one of the two possible isomeric side chains. The mechanistic details of these reactions have been substantiated by means of deuterium labelling studies. The aromatic nitriles also undergo photosubstitution by 2, in acetonitrile-methanol solution, resulting in methanol-incorporated products. Whereas reaction with 1 or 5 results in substitution of a cyano group, 6 was observed to give isomeric dicyanocyclohexenes, resulting from initial reaction at the 4-position, followed by reduction. A detailed mechanism for this secondary photoreduction has been substantiated by deuterium labelling studies. The anomalous behaviour of 1,3-dicyanobenzene has been attributed to a difference in the react~vity of the radical anion. marquages par le deutCrium permettent de confirmer les dttails mkcanistiques dc ces rCactions. Les nitriles aromatiques, en solution dans des milanges d'acktonitrile et de methanol, subissent aussi des photosubstitutions par 2; il y a formation de produits ayant incorporC du mCthanol. Alors que la rCaction des composCs 1 ou 5 conduit a la substitution d'un groupe cyano, on a observC que le compost 6 donne des dicyanocyclohextnes isomkres qui resultent d'une rkaction initiale en position 4, suivie d'une riduction. Des Ctudes impliquant des marquages par du deuterium ont permis de confirmer le mCcanisme dCtaillC de cette photorCduction secondaire. On attribue Ie comportement anormal du dicyano-I ,3 benzkne a la diffkrence de rCactivitC de I'anion radical.[Traduit par le journal]

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“…The difference in regiochemistry between the singlet oxygen and electrontransfer-sensitized photooxygenation of 29 probably arises from a different sequential addition of nucleophile and oxygen reactive species, as a result of different reactivities of the intermediates. Interception of intermediate radical cations by external and/or internal nucleophiles in photosensitized reactions have also been reported by Arnold [130], Foote et al [131]. Thus, a different stereoand/or regiochemical course of sensitized photooxygenation reactions should be desirable to place in order a diagnostic test for distinguishing between singlet oxygen and electron-transfer (both Foote-type and Barton-type) oxygenations.…”

mentioning

confidence: 73%

Photoinduced electron transfer oxygenations

Lopez

1990

Topics in Current Chemistry

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Radical ions in photochemistry. 5. Photosensitized (electron transfer) cyanation of olefins

Cited by 81 publications

References 2 publications

Organic Photoredox Catalysis

Organic Photoredox Catalysis

Radical ions in photochemistry. 15. The photosubstitution reaction between dicyanobenzenes and alkyl olefins

Photoinduced electron transfer oxygenations

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