4281-04-3Relevant articles and documents
UV photoelectron spectroscopic and computational study of 7-substituted cycloheptatrienes
Bajorek,Werstiuk
, p. 444 - 450 (2008)
The He(I) photoeiectron (PE) spectra of cycloheptatriene (1), 7-methylcycloheptatriene (2), 7-methoxycycloheptatriene (3), 7-methylthiocycloheptatriene (4), and 7-diemthylaminocycloheptatriene (5) were recorded and interpreted using MO energies and ionization potentials acquired from B3PW91 calculations. Partial simulated PE spectra were in good agreement with the experimental results. The axial and equatorial conformers have distinct PE spectra as illustrated by simulation. The PE spectra of 2, 3, and 5 are representative of the equatorial conformers, while the PE spectrum of 4 was in accord with a 1:1 mixture of equatorial and axial conformational isomers based on spectral simulation. The calculated free energy differences between the equatorial and axial conformers are in the order of 2 kcal mol-1 (1 cal = 4.184 J) for compounds 2, 3, and 5, where the equatorial conformational isomer is lowest in energy. In the case of 4, the equatorial conformer was only marginally lower in energy than its axial counterpart, where the free energy difference is 0.1 kcal mol-1.
Gold Catalysts Can Generate Nitrone Intermediates from a Nitrosoarene/Alkene Mixture, Enabling Two Distinct Catalytic Reactions: A Nitroso-Activated Cycloheptatriene/Benzylidene Rearrangement
Cheng, Mu-Jeng,Kardile, Rahul Dadabhau,Kuo, Tung-Chun,Liu, Rai-Shung,More, Sayaji Arjun
supporting information, p. 5506 - 5511 (2021/07/31)
Gold-catalyzed reactions of cycloheptatrienes with nitrosoarenes yield nitrone derivatives efficiently. This reaction sequence enables us to develop gold-catalyzed aerobic oxidations of cycloheptatrienes to afford benzaldehyde derivatives using CuCl and nitrosoarenes as co-catalysts (10-30 mol %). Our density functional theory calculations support a novel nitroso-activated rearrangement, tropylium → benzylidene. With the same nitrosoarenes, we developed their gold-catalyzed [2 + 2 + 1]-annulations between nitrosobenzene and two enol ethers to yield 5-alkoxyisoxazolidines using 1,4-cyclohexadienes as hydrogen donors.
7-METHYL- AND 7-PHENYLCYCLOHEPTA-1,3,5-TRIENES FROM BENZVALENE VIA 3,3a,4,5,6,6a-HEXAHYDRO-4,5,6-METHENOCYCLOPENTAPYRAZOLES AND TETRACYCLO2,4.03,5>HEPTANES
Christl, Manfred,Brunn, Erich,Roth, Wolfgang R.,Lennartz, Hans-Werner
, p. 2905 - 2916 (2007/10/02)
The addition of benzvalene (1) to diazomethane, diazoethane, 2-diazopropane, phenyldiazomethane, and diphenyldiazomethane afforded the 1-pyrazolines 2a-g in good yields.By means of competition experiments, the relative reactivities of benzvalene (1) and norbornene with regard to diazomethane and 2-diazopropane have been determined.The fact that benzvalene reacts about twice as fast as norbornene with both diazoalkenes cannot be rationalized on the basis of frontier orbital energies.On direct photolysis, the pyrazolines 2a-g were converted into the tetracyclo2,4.03,5>heptanes 4a-g exclusively.These compounds gave the 1,3,5-cycloheptatrienes 5a,b,d,e,g in high yields on treatment with silver ions, thus providing better access to 7,7-dimethyl-(5d) and 7,7-diphenylcycloheptatriene (5g) than before.Surprisingly, the latter compound is in equilibrium with a substantial quantity of the norcaradiene form.The heat of reaction for the rearrangement of 4a to 5a has been determined, which allows to derive the heat of formation of tetracyclo2,4.03,5>heptane (4a).
Absorption Spectra and Photochemical Rearrangements of Xylene and Methylcycloheptatriene Cations in Solid Argon
Kelsall, Benuel J.,Andrews, Lester,McGarvey, Glenn J.
, p. 1788 - 1795 (2007/10/02)
Matrix photoionization experiments have been performed for several p-dialkylbenzenes and alkylcycloheptatrienes.Broad absorptions at 23500 and 34700 cm-1 following UV matrix two-photon ionization of p-xylene are assigned to the parent cation, in agreement with photodissociation spectra of gaseous cation.A broad absorption at 20240 cm-1 following vacuum-UV matrix photoionization of 7-methylcycloheptatriene is assigned to the parent cation, in agreement with the difference between photoelectron bands.Mercury arc photolysis has been used to activate the extensive rearrangements of the p-xylene and 7-methylcycloheptatriene cations, which finally rearrange to a common conjugated triene cation identified as a substituted methylenecyclohexadiene cation.
