Untersuchungen in der Bicyclo‐[2,2,2]‐octan Reihe. 1. Mitteilung. Synthese von Bicyclo‐[2‐2‐2]‐octadien‐(2,5) durch cis‐Eliminierung

Grob, C. A.; Kny, H.; Gagneux, André R.

doi:10.1002/hlca.19570400116

Cited by 49 publications

(8 citation statements)

References 16 publications

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“…The thermal lability of derivatives of bicyclo[2.2.2]octa-2, 5-diene is well documented [14]. In the present case the decomposition of II to give benzene and cyclobutene and the decomposition of the latter in turn to 1,3-butadiene would agree with the proposed structure.…”

Section: IIsupporting

confidence: 87%

Photochemical Addition of Benzene to Cyclobutene

Srinivasan

1971

IBM J. Res. & Dev.

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The major products of the photochemical addition at 253.7 nm of benzene to cyclobutene in solution were found to be tetracyclo[5.3.0.0 2,1003,6]-decene-8 and tricyclo[4.2.2.0 2,5]deca-7,9-diene, which arise from 1,3-and lA-additions. The quantum yields for both reactionswereindependent of benzene concentrationbelow2M but decreased at higherconcentrations. The maximum quantum yields that were obtained are 0.81 and 0.09 for the 1,3-and lA-reactions, respectively, indicating that the former reaction is a very efficient process.The 1,3-addition may occurfrom the singlet(lB 2u ) state of benzene, as has beensuggested in the literature.The originof the 1A-addition is not clear, but it seems unlikely that it occursfrom the triplet state of benzene. 34

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Section: IIsupporting

confidence: 87%

Photochemical Addition of Benzene to Cyclobutene

Srinivasan

1971

IBM J. Res. & Dev.

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“…However, upon heating a C 6 D 6 solution of 2 at 150 °C, a clean ring opening occurred, giving rise to 1 quantitatively. Note that the Diels–Alder reaction between benzene and ethylene as well as the retro Diels–Alder reaction have scarcely been described thus far, 15 despite the extensive application of the elementary reactions in organic synthesis. 16 …”

Section: Results and Discussion Experimentalmentioning

confidence: 99%

Reversible [4 + 2] cycloaddition reaction of 1,3,2,5-diazadiborinine with ethylene

Ganguly

et al. 2015

Chem. Sci.

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“…The theoretical shielding effect of a benzene ring can be easily calculated from the molecular geometry according to Johnson and Bovey's method (27). …”

Section: Compoundmentioning

confidence: 99%

N.M.R. Studies of Bridged Ring Systems: Ii. Unusual Magnetic Deshielding Effect on the Bridge Methylenes of Norbornadiene and Benzonorbornadiene

Tori¹,

Hata²,

Muneyuki³

et al. 1964

Can. J. Chem.

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Proton magnetic resonance spectra of some norbornane derivatives having double bonds and (or) a benzene ring in the skeleton were studied. Differences in the chemical shifts between the bridge methylenes of norbornene and benzonorbornene and that of norbornane result from the diamagnetic anisotropy effect of a double bond or a benzene ring being in good agreement with the values calculated theoretically. However, in the norbornadiene derivatives which have two double bonds or one olefinic double bond with a benzene ring in a part of the skeleton, the signals of their bridge methylenes show extraordinarily larger downfield shifts by about 0.8 p.p.m. than those expected from the additive shielding due t o each T-electron system. This anomaly is not observed in bicyclo[2.2.2]octane ring series. A large transannular interaction between two a-electron systems in that system would be a major contribution to the above anomaly. , I N T R O D U C T I O SI11 the past few years a number of proton magnetic resonance (n.1n.r.) spectra of bridged ring systems have been investigated, reporting the relations between the spin coupling constants of ring protons and the stereochemistry (1-lo), various types.of long-range spill couplings (3, 5 , 6, 8-11), the establishment of the configuration of substituents by the evaluation of diamagnetic shielding effects of a double bond or a benzene ring (9, 12-15), and so forth (16)(17)(18)(19). However, the substantial features of n.m.r. spsctra of bicyclo[2.2.l]heptane derivatives have not received much attention. By the studies of various ~nonohydroxyl derivatives of bicyclo[2.2.l]heptane1 RIusher (8) has recently reported that (i) a striliitlgly large difference in the magnetic shielding between an exo and an endo proton was obserr~ed, showing larger deshielding on the exo proton, and this difference can not be explained only by the diamagnetic anisotropy of the C-C bonds in the ring; that (ii) the coupling constants between each pair of adjacent protons, JHx-Hx and JIIn-H,*, are not equal; and that (iii) fairly large long-range spin coupling constants were found. On the basis of these results, he suggested the presence of some n-characters in this ring system. I11 a previous paper (20), we also suggested the presence of this character on the basis of the increased s-character of the C-H bonds, which was reflected in the strikingly large values of carbon-hydrogen spin coupling constants J G~~-H obtained from the C13-satellites (21)

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Untersuchungen in der Bicyclo‐[2,2,2]‐octan Reihe. 1. Mitteilung. Synthese von Bicyclo‐[2‐2‐2]‐octadien‐(2,5) durch cis‐Eliminierung

Cited by 49 publications

References 16 publications

Photochemical Addition of Benzene to Cyclobutene

Photochemical Addition of Benzene to Cyclobutene

Reversible [4 + 2] cycloaddition reaction of 1,3,2,5-diazadiborinine with ethylene

N.M.R. Studies of Bridged Ring Systems: Ii. Unusual Magnetic Deshielding Effect on the Bridge Methylenes of Norbornadiene and Benzonorbornadiene

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