The photochemical nucleophile–olefin combination, aromatic substitution (photo-NOCAS) reaction (Part 4): methanol–olefins, methyl 4-cyanobenzoate

1993 ◽  
Vol 71 (4) ◽  
pp. 450-468 ◽  
Author(s):  
Kevin McMahon ◽  
Donald R. Arnold
Keyword(s):  
Charge Transfer ◽  
Radical Cation ◽  
Charge Transfer Complex ◽  
Cyano Group ◽  
Aromatic Substitution ◽  
Mixture Formation ◽  
Reaction Conditions ◽  
Aromatic Molecules ◽  
Aromatic Esters ◽  
Methanol Solutions

Dicyanobenzene-1,4 (1) and -1,2 are known to undergo substitution upon irradiation, in the presence of an olefin, in acetonitrile–methanol (3:1) solution. The products are 1:1:1 (methanol:olefin:aromatic) adducts, substituted on the aromatic ring with loss of a cyano group. This reaction, referred to as the photo-NOCAS (nucleophile–olefin combination, aromatic substitution) reaction, has been shown to be fairly general with regard to the olefin and the nucleophile that can be incorporated. Less is known about the scope of the reaction incorporating other electron-withdrawing substituted aromatic molecules. The purpose of this study was to determine if methyl 4-cyanobenzoate (10) would also take part in this reaction, to form 4-substituted aromatic esters. Irradiation of acetonitrile–methanol solutions of 10 and olefins 2,3-dimethyl-2-butene (2) and 1-methylcyclohexene (5) gave cyclic imine esters, 11 and 13, respectively, instead of photo-NOCAS products. The photo-NOCAS products were obtained when the codonor biphenyl (4) was added to the irradiation mixture. Formation of the cyclic imine ester is attributed to excitation of the charge-transfer complex formed between 10 and the olefin. The addition of biphenyl (4) serves to generate the contact radical ion pair (CRIP) upon irradiation of the charge-transfer complex between 10 and 4. This CRIP can dissociate to the solvent-separated radical ions, the radical cation of 4 can accept an electron from the olefin, and the olefin radical cation can go on to give the photo-NOCAS products. Irradiation of a solution of 10 and 2 in nonpolar solvent (benzene) gave the oxetane, believed to arise from the exciplex. In addition to photo-NOCAS products from 10, 4-cyanophenylketones 17 and 23 are also formed by attack of the β-alkoxyalkyl radical at the carboxyl carbonyl. The differences in behaviour between 1,4-dicyanobenzene (1) and methyl 4-cyanobenzoate (10) under these reaction conditions are described and explained.

Photochemical nucleophile–olefin combination, aromatic substitution (photo-NOCAS) reaction. Part 6: methanol, nonconjugated dienes, and 1,4-dicyanobenzene

1994 ◽  
Vol 72 (2) ◽  
pp. 415-429 ◽  
Author(s):  
Donald R. Arnold ◽  
Kimberly A. McManus ◽  
Xinyao Du
Keyword(s):  
Electron Transfer ◽  
Double Bond ◽  
Radical Cation ◽  
Oxidation Potential ◽  
Aromatic Substitution ◽  
Double Bonds ◽  
Excited Singlet ◽  
Reaction Conditions ◽  
Methanol Solutions ◽  
Cyclic Adducts

Irradiation, through Pyrex, of an acetonitrile–methanol (3:1) solution of 1,4-dicyanobenzene (1) and 1,5-hexadiene (9) leads to formation of ortho and meta cyclic adducts (13–16) arising from the intermediate exciplex. There was no evidence for interaction between the two double bonds of this nonconjugated diene. The oxidation potential of 9 is high enough (> 3 V vs. sce) to preclude single electron transfer (SET); no photo-NOCAS products are formed. Similar irradiation of acetonitrile–methanol solutions of 1 and 2-methyl-1,5-hexadiene (10) does yield a photo-NOCAS product (17); reaction occurs only on the more heavily substituted double bond. The additional substitution on the double bond lowers the oxidation potential (2.70 V vs. sce) of this diene to the point where SET from 10 to the excited singlet state of 1 can occur. In this case, no cycloaddition products are formed; the exciplex is quenched by electron transfer. There was no evidence for interaction between the two double bonds of the initially formed radical cation 10+•, or between the terminal double bond and the β-alkoxyalkyl radical of the intermediate leading to the photo-NOCAS product. The photo-NOCAS product (19) was also formed when 2,5-dimethyl-1,5-hexadiene (11) was subjected to these reaction conditions. In this case, when biphenyl (4) was added as a codonor, in addition to the photo-NOCAS product, products (21cis and trans) resulting from cyclization of the initially formed acyclic radical cation 11+• to give the 1,4-dimethylcyclohexane-1,4-diyl radical cation were also observed. This 1,6-endo, endo cyclization of 11+• must be rapid enough to compete with reaction with methanol. There was no evidence for cyclization (neither 1,4-exo nor 1,5-endo) of the intermediate β-alkoxyalkyl radical. When the radical cation of 2,5-dimethyl-1,4-hexadiene (12+•) is generated under these reaction conditions, photo-NOCAS products 22 and 23 are formed at the more heavily substituted double bond, along with the conjugated tautomer 2,5-dimethyl-2,4-hexadiene (24). The mechanisms for these transformations are discussed.

Photochemical Nitration by Tetranitromethane. XVII. The Regiochemistry of Adduct Formation in the Photochemical Reaction of 1-Methylnaphthalene and Tetranitromethane

1994 ◽  
Vol 47 (8) ◽  
pp. 1591 ◽  
Author(s):  
JL Calvert ◽  
L Eberson ◽  
MP Hartshorn ◽  
n Maclaga ◽  
WT Robinson
Keyword(s):  
Crystal Structure ◽  
Charge Transfer ◽  
Radical Cation ◽  
Photochemical Reaction ◽  
Charge Transfer Complex ◽  
Adduct Formation ◽  
X Ray ◽  
Analogous Manner ◽  
Structure Determinations ◽  
Ion Recombination

Photolysis of the 1-methylnaphthalene/tetranitromethane charge-transfer complex yields the triad of 1-methylnaphthalene radical cation, nitrogen dioxide and trinitromethanide ion. Recombination of this triad gives predominantly 4-methyl-t-2-nitro-r-1-trinitromethyl-1,2- dihydronaphthalene (1), the epimeric 1-methyl-1-nitro-4-trinitromethyl-1,4-dihydronaphtha-lenes (2) and (3), 8-methyl-c-4-trinitromethyl-1,4-dihydronaphthalen-r-l-ol (4), nitro cyclo -adduct (5), 8-methyl-c-4-trinitromethyl-1,4-dihydronaphthalen-r-l-ol (6), hydroxy cyclo-adduct (7) and 4-methyl-t-1-trinitromethyl-1,2-dihydronaphthalen-r-2-ol (8). Adducts (1)- (3), (5), (7) and (8) are formed by attack of the trinitromethanide ion at C4 of the 1-methylnaphthalene radical cation, while adducts (4) and (6) are formed by corresponding attack at C5. Adduct (1) undergoes thermal cycloaddition to give the nitro cycloadduct (5) and it is assumed that the hydroxy cycloadduct (7) is formed in analogous manner from 4-methyl-t-1-trinitromethyl-1,2-dihydronaphthalen-r-2-ol (8). X-Ray crystal structure determinations are reported for adducts (1), (3)-(5) and (7).

Photochemical Nitration by Tetranitromethane. XIV. The Formation of 1,3-Dipolar Nitro Addition Products From the Photochemical Reaction of 1,2-Dimethylnaphthalene and Tetranitromethane

1994 ◽  
Vol 47 (6) ◽  
pp. 1087 ◽  
Author(s):  
CP Butts ◽  
JL Calvert ◽  
L Eberson ◽  
MP Hartshorn ◽  
n Maclaga ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Nitrogen Dioxide ◽  
Radical Cation ◽  
Photochemical Reaction ◽  
Charge Transfer Complex ◽  
Ion Recombination

Photolysis of the 1,2-dimethylnaphthalene/tetranitromethane charge-transfer complex yields the triad of 1,2-dimethylnaphthalene radical cation, nitrogen dioxide, and trinitromethanide ion. Recombination of this triad gives predominantly the adducts (13)-(16), each of which is formed by attack of the trinitromethanide ion at C4 of the 1,2-dimethylnaphthalene radical cation. Thermal cycloaddition in adducts (13) and (16) gives the cycloadducts (12) and (17) respectively.

A Host-Induced Intramolecular Charge-Transfer Complex and Light-Driven Radical Cation Formation of a Molecular Triad with Cucurbit[8]uril

2008 ◽  
Vol 73 (10) ◽  
pp. 3775-3783 ◽  
Author(s):  
Dapeng Zou ◽  
Samir Andersson ◽  
Rong Zhang ◽  
Shiguo Sun ◽  
Björn Åkermark ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Radical Cation ◽  
Charge Transfer Complex ◽  
Intramolecular Charge Transfer

Study on excited states of hexamethoxybenzene-NO+ charge-transfer complex: incorporation of excited radical cation

2012 ◽  
Vol 39 (1) ◽  
pp. 425-435 ◽  
Author(s):  
Nobuyuki Ichinose ◽  
Masahide Hagiri ◽  
Jun-ichiro Kinugasa ◽  
Nobuyuki Shichi ◽  
Toshihiro Nakayama
Keyword(s):  
Charge Transfer ◽  
Excited States ◽  
Radical Cation ◽  
Charge Transfer Complex ◽  
Excited Radical

Photochemical Nitration by Tetranitromethane. XXIX. Adduct Formation in the Photochemical Reaction of Tetranitromethane and 1,5-Dimethylnaphthalene; Allylic Rearrangements of Adducts

1995 ◽  
Vol 48 (12) ◽  
pp. 1989 ◽  
Author(s):  
CP Butts ◽  
L Eberson ◽  
MP Hartshorn ◽  
WT Robinson
Keyword(s):  
Charge Transfer ◽  
Radical Cation ◽  
Charge Transfer Complex ◽  
Major Product ◽  
Adduct Formation ◽  
Allylic Rearrangement ◽  
X Ray ◽  
Structure Determinations ◽  
Carbon Radicals ◽  
Nitronic Ester

Photolysis of the 1,5-dimethylnaphthalene/tetranitromethane charge-transfer complex yields the triad of 1,5-dimethylnaphthalene radical cation, nitrogen dioxide and trinitromethanide ion. Recombination of this triad gives predominantly the epimeric 4,8-dimethyl-1-nitro-4-trinitromethyl-1,4-dihydronaphthalenes (18) and (27), the epimeric 1,5-dimethyl-1-nitro-4-trinitromethyl-1,4-dihydronaphthalenes (20) and (21), 4,8-dimethyl-r-1-nitro-t-2-trinitromethyl-1,2-dihydronaphthalene (19), 4,8-dimethyl-t-2-trinitromethyl-1,2-dihydronaph-thalen-r-1-ol (23), nitro cycloadduct (22), hydroxy cycloadduct (24), nitronic ester (25) and 4,8-dimethyl-1-nitronaphthalene (26). Adduct (19) is formed substantially by allylic rearrangement of 4,8-dimethyl-1-nitro-4-trinitromethyl-1,4-dihydronaphthalene (18), and adduct (23) and indirectly nitronic ester (25) by allylic rearrangement of a postulated intermediate 4,8-dimethyl-t-4-trinitromethyl-1,4-dihydronaphthalen-r-1-ol (32). Adducts (18), (19), (23), (25) and (27) are formed by attack of trinitromethanide ion at C 1 of the 1,5-dimethylnaphthalene radical cation, while adducts (20)-(22) and (24) are formed by the corresponding attack at C4, the reaction pathways being determined by the relative energies of the intermediate delocalized carbon radicals. Adduct formation is substantially suppressed for a photolysis when trifluoroacetic acid (0.7 M) is added to the dichloromethane solvent at 20°, 1,5-dimethyl-4-nitronaphthalene (26) being formed close to quantitatively. In contrast, photolysis of the 1,5-dimethylnaphthalene/tetranitromethane charge-transfer complex in 1,1,1,3,3,3-hexafluoropropan-2-ol gave substantial amounts of adduct (19), together with 1,5-dimethyl-4-nitronaphthalene (26) as the major product. Allylic rearrangements of 1-methoxy-4-nitro-1-trinitromethyl-1,4-dihydronaphthalene (34) and the epimeric 1,4,5,8-tetramethyl-1-nitro-4-trinitromethyl-1,4-dihydronaphthalenes (38) are seen as the mode of formation of 4-methoxy-r-1-nitro-t-2-trinitromethyl-1,2-dihydronaphthalene (33) and the epimeric 1,4,5,8-tetramethyl-1-nitro-2-trinitromethyl-1,2-dihydronaphthalenes (36), respectively. X-Ray crystal structure determinations are reported for adducts (19), (20), (22), (24) and (28), the last compound being formed only on chromatography of reaction mixtures.

Photochemical Nitration by Tetranitromethane .XVI. The Regiochemistry of Adduct Formation in the Photochemical Reaction of 1,8-Dimethylnaphthalene and Tetranitromethane; Thermal 1,3-Dipolar Nitro Addition Reactions

1994 ◽  
Vol 47 (7) ◽  
pp. 1211 ◽  
Author(s):  
JL Calvert ◽  
L Eberson ◽  
MP Hartshorn ◽  
n Maclaga ◽  
WT Robinson
Keyword(s):  
Charge Transfer ◽  
Nitrogen Dioxide ◽  
Radical Cation ◽  
Photochemical Reaction ◽  
Charge Transfer Complex ◽  
Adduct Formation ◽  
Addition Reactions ◽  
X Ray ◽  
A Minor ◽  
Trinitromethyl Group

Photolysis of the 1,8-dimethylnaphthalene/tetranitromethane charge-transfer complex yields the triad of 1,8-dimethylnaphthalene radical cation, nitrogen dioxide, and trinitromethanide ion. In dichloromethane at +20° recombination of this triad gives predominantly the adducts (8), (9), (11), and (14), each of which is formed by attack of the trinitromethanide ion at C4 of the 1,8-dimethylnaphthalene radical cation; a minor adduct (10) is formed by similar attack but at C3 of the aromatic radical cation. The cycloadducts (12) and (13) arise by cycloaddition of the trinitromethyl group to the alkene function in adducts (9) and (14). The cycloaddition (9)→(12) has been shown to be a thermal, not photochemical, reaction. X-Ray crystal structures are reported for adducts (8) and (12).

Charge-transfer complex and radical cation salt of a new donor EDT-TTFCL2: unique conductivities and crystal structures

1996 ◽  
Vol 6 (3) ◽  
pp. 501 ◽  
Author(s):  
Masahiko Iyoda ◽  
Hironori Suzuki ◽  
Shigeru Sasaki ◽  
Harukazu Yoshino ◽  
Koichi Kikuchi ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Crystal Structures ◽  
Radical Cation ◽  
Charge Transfer Complex ◽  
Radical Cation Salt
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