Nuclear Magnetic Resonance Spectra of Some Norbornadienes and Norbornenes

Snyder, Eugene I.; Franzus, Boris

doi:10.1021/ja01060a043

Cited by 100 publications

(29 citation statements)

References 4 publications

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“…The methyl protons gave rise to sharp, well-resolved doublets with 'JpH = 2.3-2.6 Hz. It should be noted for the two homoallylic systems (e.g., 8 and 10) that > 'J; the reasons for this effect are not apparent, but the lack of attenuation of short-range 31P-1H coupling constants with distance is well established. '* The substitution of an oxygen atom for the methylene group of this homoallylic system produces an attenuation of the magnitude of 7JpH, but the coupling (0.6-0.9 Hz) is readily observable in thep-tolyl phosphates 22 and 23.…”

Section: E Griffin and M Gordon2mentioning

confidence: 99%

Long-range phosphorus-31-hydrogen-1 spin-spin couplings in benzyl and tolyl phosphorus compounds

Griffin¹,

Gordon²

1967

J. Am. Chem. Soc.

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Examination of the spectra of a series of tolyl-and benzylphosphonium salts, phosphonates, and phosphine oxides shows the existence of two types of long-range 31P-1H spin-spin couplings. Four-bond allylic couplings (1-2.5 Hz) are observed in both series of compounds; the magnitude of 4 J~~ depends upon the position of attachment (sp2 or sp3 carbon) of phosphorus to the allylic triad. Both five-and seven-bond homoallylic couplings are observed in the benzylphosphorus systems. The magnitudes of 'JPH (2.3-2.6 Hz) are greater than those of ?]pH (1 ,1-1,7 Hz). Neither six-bond couplings in the benzyl series nor five-and six-bond couplings in the tolyl analogs are observed. Both inductive hyperconjugation and overlap hyperconjugation coupling mechanisms are considered for the homoallylic interactions; on the basis of certain consistent patterns of JPH behavior and the study of model compounds, the latter mechanism is favored.nvestigations of the proton magnetic resonance spectra

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Section: E Griffin and M Gordon2mentioning

confidence: 99%

Long-range phosphorus-31-hydrogen-1 spin-spin couplings in benzyl and tolyl phosphorus compounds

Griffin¹,

Gordon²

1967

J. Am. Chem. Soc.

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“…On the other hand, some remarkable features have been reported in the nuclear magnetic resonance (n.1n.r.) spectra of the bridge protons of norbornenyl and norbornadienyl derivatives and their benzo analogues (2)(3)(4)(5)(6). 'All correspondence concerning this paper should be addressed t o this author.…”

Section: Introductionmentioning

confidence: 99%

“…First is the stereospecific long-range spin coupling between the bridge proton and the ring endo-ethano or vinyl protons anti to it (2,3,5).3econdly, in norbornene and benzonorbornene, the anti bridge proton signal appears a t a higher field than does the syn proton signal (6). To comprehend these results, a stereospecific orbital interaction between the w-electron system of the ring carbons and the orbital system of the bridge carbon has been discussed with reference to its pronounced participation in the solvolysis reactions of 7-norbornenyl derivatives (3).…”

Section: Introductionmentioning

confidence: 99%

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Substituent effects on the chemical shifts of the bridge protons of benzonorbornenes

Inamoto¹,

Masuda²,

Tori³

et al. 1967

Can. J. Chem.

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The substituetlt effects on the chemical shifts of the Cg bridge protons in a scries of 6-substituted benzonorbornenes and benzonorbornadienes, and on those of the Cz protons in 6-substituted 2-indanols, were investigated. They were linearly correlated with the modified Hammett relationship 7, -7, = p(um + uP)/2. The p values obtained from the anti-Co protons in the bornenes and bornadienes were slightly but significantly larger than those from the corresponding syn protons, whereas no significant difference was observed between the p values obtained from syn-9-benzonorbornenols and the indanols. The larger pa,,, values were explained in terms of a stereospecific electronic interaction between the T-electron system of the benzene ring and the orbital system of the bridge carbon. In addition, it was shown that the above modified Hammett relationship gives generally a good agreement with the substituent effects on the aliphatic constituents of benzocyclenes and analogous compounds.

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“…part). The exo-2-hydroxy and endo-3-chloro substitution was confirmed by measuring typical coupling constants between the bridgehead protons H-C (l), H-C (4) and the adjacent H-C (2) and H-C(3) ( J H~*~-C (~) , H -C (~) = 33-4 Hz; JHendo.C(2),H-C(I)~0 Hz [3] 1241 [26]). Chromium trioxide oxidation of 18 gave the expected chloroketone 19 whose 'H-NMR.…”

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confidence: 99%

Selective Hydrogen Chloride Elimination from Primary Chlorides Induced by the Fluoride Anion. Anchimeric participation of the chloromethyl group in the heterolytic opening of an epoxide. Stereospecific syntheses of 5,6‐bis (methylidene)‐syn‐2‐norbornen‐7‐ol and 5,6‐bis (methylidene)‐endo‐3‐chloro‐exo‐2‐norbornanol

Chollet

Hagenbuch

Vogel

1979

Helvetica Chimica Acta

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SummarySyntheses of the alcohols 10 and 18, and the corresponding ketones 11 and 19 are presented. Endo-5, exo-6-bis (chloromethyl)-endo-3-chloro-exo-2-norbornanol (16) and endo-5-(bromomethyl)-exo-6-(chloromethyl)-endo-3-chloro-exo-2-norbornanol (17) were obtained by HC1-and, respectively, HBr-addition to endo-5, exo-6-bis (chloromethyl)-exo-2,3-epoxynorbornane (5). The Wagner-Meerwein rearrangement was precluded in these reactions probably because of the formation of a relatively stable chloronium ion 15 arising from the participation of the 1,Cchlorine atom of the endo-5-chloromethyl group in the heterolytic ring opening of the epoxide 5.The 'naked' fluoride anion (excess CsF in DMF or KF in DMF with 18-crown-6-ether) permitted the selective elimination of 2 equivalents of HC1 from 16 and yielded the chlorohydrin-diene 18.

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Nuclear Magnetic Resonance Spectra of Some Norbornadienes and Norbornenes

Cited by 100 publications

References 4 publications

Long-range phosphorus-31-hydrogen-1 spin-spin couplings in benzyl and tolyl phosphorus compounds

Long-range phosphorus-31-hydrogen-1 spin-spin couplings in benzyl and tolyl phosphorus compounds

Substituent effects on the chemical shifts of the bridge protons of benzonorbornenes

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