1609-39-8Relevant academic research and scientific papers
Absorption Spectra and Photochemical Rearrangements of 1-, 2-, and 3-Chlorocycloheptatriene, 7-Chloronorbornadiene, and Benzyl Chloride Cations in Solid Argon
Andrews, Lester,Kelsall, Benuel J.,Payne, Christopher K.,Rodig, Oscar R.,Schwarz, Helmut
, p. 3714 - 3721 (1982)
Matrix photoionization of chlorocycloheptatriene (CCHT) during condensation with excess argon at 20 K produced new broad 484-, 517-, and 544-nm bands, a sharp 469.3-nm absorption, and weak 453- and 468-nm bands.The broad bands are assigned to the 1-, 2-, and 3-chlorocycloheptatriene cations.Photolysis with 500- 1000-nm radiation decreased the broad bands and increased the sharp 469.3-nm absorption.The 469.3-nm band and a sharp 707.8-nm counterpart in benzyl chloride experiments suggest a conjugated triene cation identification with 6-chloro-5-methylene-1,3-cyclohexadiene cation (3) as the most reasonable possibility.The 453- and 468-nm bands, which markedly increased on near-UV photolysis in benzyl chloride experiments, were strong products in similar studies with 7-chloronorbornadiene.Photolysis with 470-1000-nm radiation decreased the 468-nm band and increased the 453-nm absorption; this interconversion was reversed with 370-460-nm radiation.The latter bands are probably due to E and Z isomers of 5-(chloromethylene)-1,3-cyclohexadiene cation (6), which isomerize upon photoexcitation.
The Norbornadiene Route to Prostaglandin I2 and Other Prostaglandins: Preparation and Rearrangement of 7-Substituted Norbornadienes
Baxter, Anthony D.,Roberts, Stanley M.,Scheinmann, Feodor,Wakefield, Basil J.,Newton, Roger F.
, p. 932 - 933 (1983)
The cyclopentenylacetaldehyde (1) required for the synthesis of prostacyclin (prostaglandin I2) and other prostanoids is now readily available from the preparation and rearrangement of 7-substituted norbornadienes.
Influence of carbocation stability in the gas phase on solvolytic reactivity: Beyond bridgehead derivatives
Abboud, Jose-Luis M.,Alkorta, Ibon,Davalos, Juan Z.,Mueller, Paul,Quintanilla, Esther,Rossier, Jean-Claude
, p. 3786 - 3796 (2007/10/03)
The intrinsic gas-phase stability of bicyclic secondary carbocations has been determined by Dissociative Proton Attachment of chlorides and alcohols, respectively. From these data, Gibbs free energies for hydride transfer relative to 1-adamantyl (ΔrG°(8,exp)) are derived after application of appropriate leaving group corrections, and good agreement with theoretical values, (ΔrG°(8,comp)), calculated at the G2(MP2) or MP2/6-311G(d,p) level, is reached (Table 1). The relative rate constants for solvolysis (log(k/k0)) of the bicyclic secondary derivatives correlate with the stabilities of the respective carbocations in the same manner as tertiary bridgehead derivatives, but simple monoderivatives and acyclic derivatives solvolyze faster than predicted on the grounds of the ion stabilities. The corresponding stabilities of cyclopropyl- and benzyl-substituted carbocations have been obtained by a combination of experimental and computational data available in the literature with computational methods. Correlation of the rate constants for solvolysis vs ion stabilities for these compounds reveals a trend similar to that observed for bridgehead derivatives, but with much more scatter, which is attributed to nucleophilic solvent participation and/or nucleophilic solvation.
Gas-phase pyrolysis mechanism and kinetics of 3-chloroquadricyclane
Alfano, Angelo J.
, p. 689 - 694 (2007/10/03)
The gas-phase pyrolysis of 3-chloroquadricyclane [1] was investigated over the temperature range 513-550 K at one atm in helium. The initial pyrolysis step is the isomerization of 3-chloroquadricyclane to 7-chloronorbornadiene (Ea = 39.63 ± 1.4
Solvolysis of tricyclo[4.1.0.02,7]hept-4-en-3-yl and tricyclo[4.1.0.02,7]hept-3-yl methanesulfonates and p-nitrobenzoates - Remarkably small enthalpy difference between the C7H7 cations tricyclo[4.1.0.02,7]hept-4-en-3-yl and 7-norbornadienyl
Bentley, T. William,Llewellyn, Gareth,Norman, Simon J.,Kemmer, Ralf,Kunz, Ulrike,Christl, Manfred
, p. 229 - 244 (2007/10/03)
In an extension of previous work, tricyclo[4.1.0.02,7]heptan-3-ol (5) was synthesised in four steps from benzvalene. Methanesulfonates 12 and 6b, c, prepared from 5 and 4-halotricyclo[4.1.0.02,7]hept-4-en-3-ols 4b, c, were too unstable to be isolated, but were unambiguously characterised by their NMR spectra. On treatment of the unsubstituted tricycloheptenol 4a with methanesulfonyl chloride, the expected mesylate 6a could not be observed. Even at -40°C, only its consecutive products 3-chlorotricyclo[4.1.0.02,7]hept-4-en (7a) and 7-chloronorbornadiene (8a) were discernible. The analogous reaction of 6b occurred only at room temperature, with formation of the dichlorotricycloheptene 7b and the dichloronorbornadiene 8b. Rearrangement products of 6b and 12 were the chloronorbornadiene mesylate 10b and anti-7-norbornenyl mesylate (13), respectively. - The solvolysis of 6b, c in aqueous ethanol and of 6b in 2,2,2-trifluoroethanol (TFE) gave nonrearranged products exclusively, i.e. the alcohols 4b, c, the ethyl ethers 17b, c, and the trifluoroethyl ether 18b. In contrast, from 12 only rearranged products arose, namely anti-7-norbornenol (30) and its ethyl ether 31. The solvolysis of the unsubstituted tricycloheptenyl p-nitrobenzoate 11a in 80% aqueous ethanol proceeded about equally fast in parallel reactions with cycloalkyl-oxygen and acyl-oxygen cleavage. In addition to the tricycloheptenol 4a, the tricycloheptenyl ethyl ether 17a, ethyl 7-norbornadienyl ether (19), 7-norbornadienyl p-nitrobenzoate (20), and ethyl p-nitrobenzoate were formed. No acyl-oxygen cleavage took place in TFE as solvent, where the tricycloheptenyl trifluoroethyl ether 18a, 20, 7-norbornadienyl trifluoroethyl ether (21), and the cyclopentadienylvinyl trifluoroethyl ethers 22/23 were produced. A new mechanism is proposed for the route to the major products 22/23 via the intermediate 7-norbornadienyl cation (9a), which was attacked by TFE at the two-membered bridge stabilising the positive charge. Thus formed, tricyclo[3.2.0.02,7]hept-3-en-endo-6-yl trifluoroethyl ether (24) underwent a Diels-Alder cycloreversion generating the cyclopentadienylvinyl trifluoroethyl ether 25, the immediate precursor of 22/23. - From kinetic data for these processes and thermochemical data for appropriate hydrocarbons, the enthalpy difference between the C7H7 cations, tricyclo[4.1.0.02,7]hept-4-en-3-yl (3a) and 7-norbornadienyl (9a), was calculated to be only 8 kcal mol-1. VCH Verlagsgesellschaft mbH, 1997.
Catalysis of the thermal quadricyclane -> norbornadiene isomersation by mercury(II) halides
Rood, I. D. Ch.,Klumpp, G. W.
, p. 303 - 304 (2007/10/02)
Quadricyclanes are rapidly isomerised to norbornadienes by Hg(II) halides under very mild conditions, corner-mercuration being assumed to be the essential step.With quadricyclane and 3-tert-butyl-quadricyclane, zero-order kinetics were found.
