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Norbornadiene

About: Norbornadiene is a research topic. Over the lifetime, 2389 publications have been published within this topic receiving 38603 citations.


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Journal ArticleDOI
TL;DR: In this paper, a synthetic procedure was developed for preparation of exo-oriented di- and tetraamines of the norbornane series by 1,3-dipolar cycloaddition to norbornene and norbornadiene of generated in situ diazomethane followed by reduction of arising pyrazolines catalyzed by Raney nickel.
Abstract: Synthetic procedure was developed for preparation of exo-oriented di- and tetraamines of the norbornane series by 1,3-dipolar cycloaddition to norbornene and norbornadiene of generated in situ diazomethane followed by reduction of arising pyrazolines catalyzed by Raney nickel.

4 citations

Journal ArticleDOI
TL;DR: In this paper, the reaction of (+)-9-phenyldeltacyclanyl moiety as a chiral phosphorus substituent contains eight configurationally fixed asymmetric carbon atoms.
Abstract: The (+)-9-phenyldeltacyclanyl moiety as a chiral phosphorus substituent contains eight configurationally fixed asymmetric carbon atoms. It is easily obtained from the reaction of norbornadiene and phenylacetylene via a Co-catalyzed enantioselective homo-Diels−Alder reaction, to give (+)-8-phenyldeltacyclene. In the reaction of (+)-8-phenyldeltacyclene with 1,2-(H2P)2C6H4 the trisubstitution product P,P,P′-tris[(+)9-phenyldeltacyclan-8-yl)-1,2-bis(phosphanyl)benzene, (+)δ-LH, is obtained, in which a single P−H bond at the stereogenic phosphorus atom is left. (+)δ-LH crystallizes as a pure diastereomer, which isomerizes in solution with respect to the secondary phosphorus atom at −20 °C resulting in a 64:36 diastereomer mixture. Substitution of the P−H hydrogen atom in (+)δ-LH by benzyl, 3-bromobenzyl, 6-bromo-n-hexyl and 3-(diphenylphosphanyl)phenyl gave the bis(tertiary) diphosphanes (+)δ-LR1−(+)δ-LR4. NiBr2, PdHal2 (Hal = Cl, Br, I) and PtHal2 (Hal = Cl, Br) complexes of (+)δ-LH and (+)δ-LR1−(+)δ-LR4have been synthesized. The complexes form two diastereomers differing in the configuration of the chiral P atom. X-ray structure analyses have been carried out with (+)δ-LH, [(+)δ-LR2]NiBr2, [(+)δ-LH]PdI2 and [(+)δ-LCl]PdI2. Interestingly, for [(+)δ-LH]PdI2 both diastereomers are found in the same crystal lattice in a 1:1 ratio. In [(+)δ-LH]PdI2 and [(+)δ-LCl]PdI2the configuration at the secondary phosphorus atom is stable in solution at room temperature, whereas in the free ligand (+)δ-LH it is configurationally labile. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

4 citations

Journal ArticleDOI
TL;DR: A new method was developed for the direct synthesis of the second representative of the homologous series of diamond-like hydrocarbons, diamantane, in 65% yield by hydroisomerization of the norbornadiene dimer, endo-endo-heptacyclo in 68% yield with excellent selectivity.
Abstract: A new method was developed for the direct synthesis of the second representative of the homologous series of diamond-like hydrocarbons, diamantane, in 65% yield by hydroisomerization of the norbornadiene dimer, endo-endo-heptacyclo[8.4.0.02,12.03,8.04,6.05,9.011,13]tetradecane (binor-S) on treatment with concentrated sulfuric acid (98%). In the presence of H2SO4 of lower concentration (75-80%), the reaction stops after the hydrogenation step giving endo-endo-pentacyclo[7.3.1.12,5.18,10.03,7]tetradecane in 68% yield with excellent selectivity (100%).

4 citations

Journal ArticleDOI
TL;DR: An alternative skeletal rearrangement of the quadricyclane radical cation (Q*+) explains the side products formed in the one-electron oxidation to norbornadiene.
Abstract: An alternative skeletal rearrangement of the quadricyclane radical cation (Q*+) explains the side products formed in the one-electron oxidation to norbornadiene. First, the bicyclo[2.2.1]hepta-2-ene-5-yl-7-ylium radical cation, with an activation energy of 14.9 kcal mol(-1), is formed. Second, this species can further rearrange to 1,3,5-cycloheptatriene through two plausible paths, that is, a multistep mechanism with two shallow intermediates and a stepwise path in which the bicyclo[3.2.0]hepta-2,6-diene radical cation is an intermediate. The multistep rearrangement has a rate-limiting step with an estimated activation energy of 16.5 kcal mol(-1), which is 2.8 kcal mol(-1) lower in energy than the stepwise mechanism. However, the lowest activation energy is found for the Q*+ cycloreversion to norbornadiene that has a transition structure, in close correspondence with earlier studies, and an activation energy of 10.1 kcal mol(-1), which agrees well with the experimental estimate of 9.3 kcal mol(-1). The computational estimates of activation energies were done using the CCSD(T)/6-311+G(d,p) method with geometries optimized on the B3LYP/6-311+G(d,p) level, combined with B3LYP/6-311+G(d,p) frequencies.

4 citations

Journal ArticleDOI
TL;DR: In this paper, the triplet sensitization in benzene was studied by γ-radiolysis and pulse radiolysis, and an equilibrium state between a 1,3-biradical intermediate and a triplet state with the structure of norbornadiene was estimated.
Abstract: The mechanism of valence isomerization between methyl 5-(4-biphenylyl) tetracyclo [3.2.0.2,70.4,6] heptane-1-carboxylate (1) and methyl 3-(4-biphenylyl)bicyclo[2.2.1]hepta-2,5-diene-2-carboxylate (2) under the triplet sensitization in benzene was studied by γ-radiolysis and pulse radiolysis. As an intermediate for the isomerization, an equilibrium state between a 1,3-biradical intermediate and a triplet state with the structure of norbornadiene has been estimated. The triplet energy levels of 1 and 2 were determined to be 59 and 57 kcal mol−1, respectively. The energy difference between the ground states of 1 and 2 was determined to be 18 kcal mol−1.

4 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202316
202240
202133
202040
201930
201829