Photochemical Addition of Benzene to Cyclobutene

Srinivasan, R.

doi:10.1147/rd.151.0034

Cited by 20 publications

(7 citation statements)

References 5 publications

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“…The ~hotoaddition of an excited state olefin to benzene or such a photoaddition involving a cyano-substituted substrate generally gives 1,2 adducts (6, 7). The photoaddition involving excited state benzenes with an olefin can give all possible 1,2, 1,3, and 1,4 adducts with retention of stereochemistry, and has been shown to be derived from a common intermediate, which appears to be benzvalene (4,5,8). In the present photoaddition, singlet excited state AABF2 is not expected to sensitize benzene from the energetic consideration nor to follow the [2 +4] addition pattern.…”

Section: Discussionmentioning

confidence: 65%

The photoaddition of 1,3-diketonatoboron difluorides with benzene derivatives

Chow¹,

Ouyang²

1991

Can. J. Chem.

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The boron difluoride complexes of 2-acetylcyclohexanone, 2-acetylcyclopentanone, and acetylacetone (abbreviated as ACHBF2, ACPBF2, and AABF2) were irradiated in the presence of benzene to give the 1:1 adducts as the primary photoadducts; for certain BF2 complexes, toluene, chlorobenzene, benzonitrile, and methyl benzoate were also used as substrates. The 1,5-diketone photoadducts were assumed to form by a [2+2] photocycloaddition followed by cyclobutane opening and hydrolysis to give 1,2 adducts. They undergo a variety of secondary thermal reactions, probably acid catalyzed, to give enol ethers, enol acetates, acetophenones, and ketonylacetophenones. The efficiency of these secondary reactions determines the final products. Photoaddition with a monosubstituted benzene preferentially occurs at the 3,4 bond without regioselectivity. Under oxygen, ACHBF2 photolytically reacts with benzene to give a secondary oxidation product of a 10-membered cyclic alkylphe-none, which is proven by X-ray crystallographic analysis to have the benzene ring and carbonyl group in orthogonal orientation. It is shown that the singlet excited state ACHBF2 initiates the photoaddition, probably through the formation of the benzene exciplex, which could be detected by its emission. While the Stern–Volmer rates are small, the quantum yield of photoaddition products is as high as 0.12–0.19 under limiting conditions. Key words: [2+2] photocycloaddition, non-planar alkanophenone, macrocyclic alkanophenone, boron difluoride complexes, photoaddition to benzenes.

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Section: Discussionmentioning

confidence: 65%

The photoaddition of 1,3-diketonatoboron difluorides with benzene derivatives

Chow¹,

Ouyang²

1991

Can. J. Chem.

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“…The structure assigned to 4 has been confirmed by independent synthesis. Photochemical addition of benzene to 3,4-dichlorocyclobutene12 produced 5,13 which on treatment with sodium anthracene in tetra-hydrofuran14 gave the tetracyclodecadiene 6.15 Intra-6 4…”

Section: Sirmentioning

confidence: 99%

Structures and isomerism of the hydrofluoroborate salts of Reissert compounds

McEwen¹,

Calabro²,

Mineo³

et al. 1973

J. Am. Chem. Soc.

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“…Presently (1972Presently ( -1973 on sabbatical leave at the Laboratory of Chemical Biodynamics, Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720. has been pointed out by Bryce-Smith (7). The light-induced additions of benzene with cyclobutene (8,9), tetramethylethylene (10, 1 I), and 2-butene (11) have been reported. The tetramethylethylene reaction is influenced by an acid catalyst (lo), suggesting that charge-transfer processes are important, cf.…”

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confidence: 92%

Photo-additions of Naphthalene Derivatives with Substituted Ethylenes: Influence of Methoxy- and Cyano-substituents on the Products

Chamberlain¹,

McCullough²

1973

Can. J. Chem.

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Irradiation of 2-methoxynaphthalene and acrylonitrile in ethanol affords exo-and endo-7-cyano-6-methoxy-2,3-benzobicyclo[4.2.0]octa-2,4-diene, in the ratio 30:70. The structures are assigned from the n.m.r. spectra. The endo compound is the more stable, and on base equilibration predominates (90%). These adducts eliminate a methoxy-group on treatment with tert-butoxide at 80a, to afford 2,3-naphthocyclobutene carboxamide. Irradiation of 2-cyanonaphthalene and methyl vinyl ether in ethanol gives a complicated mixture of adducts which includes the cyclobutane 7-methoxy-6-cyano-2,3-benzobicyclo-[4.2.0]octa-2,4-diene as a major product (35%). Also formed are 7-methoxy-2,3(8-cyanobenzo)bicyclo-[3.3.0]octa-2,7-diene (873, 8-methoxy-l0-cyano-l,2-benzocycloocta-l,3,5-triene (la%), and a dimer of the latter (779, and 8-methylene-5-methoxy-2,3(10-cyanobenzo)bicyco[2.2.I]heptene (35%). The structures of the latter adducts are assigned from spectroscopic data, including nuclear Overhauser effects. Possible mechanisms for formation of the latter adducts, and a rule for prediction of regiospecificity in cyclobutane formation, are proposed.

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Photochemical Addition of Benzene to Cyclobutene

Cited by 20 publications

References 5 publications

The photoaddition of 1,3-diketonatoboron difluorides with benzene derivatives

The photoaddition of 1,3-diketonatoboron difluorides with benzene derivatives

Structures and isomerism of the hydrofluoroborate salts of Reissert compounds

Photo-additions of Naphthalene Derivatives with Substituted Ethylenes: Influence of Methoxy- and Cyano-substituents on the Products

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