13407-18-6Relevant articles and documents
Organic Photochemistry with 6.7-eV Photons: The Photochemistry of Bicyclohept-2-ene (2-Norcarene)
Leigh, William J.,Srinivasan, R.
, p. 514 - 519 (1983)
The photochemistry of bicyclohept-2-ene (2-norcarene) upon direct and triplet-sensitized photolysis has been investigated.The results differ significantly from those of previous studies on related systems.Direct photolysis with monochromatic radiation in the region 185-230 nm leads to a variety of products, of which cis-1,3,6-heptadiene, the major product, is shown by deuterium labeling studies to result from formal electrocyclic ring opening in a manner analogous to the 1,3-cyclohexadiene/1,3,5-hexatriene interconversion.The evidence suggests that this process may occur via a concerted mechanism in the singlet state.The other products arise from activation of the two cyclopropane bonds that are in conjugation with the olefinic group.The product distribution is independent of both solvent and excitation wavelength and is unchanged by the addition of naphthalene.Toluene-sensitized photolysis results in the formation of cis-1,3,6-heptatriene and bicyclohept-2-ene, which can be rationalized as resulting from decay of a common biradical intermediate.
185-nm Photolysis and Pyrolysis of the Spirocyclopropane-Substituted Azoalkanes of 2,3-Diazatricyclo4,9>non-2-ene and Their Denitrogenated Hydrocarbon Products, the Tricyclo2,7>heptanes
Adam, Waldemar,Zang, Gerald
, p. 3315 - 3323 (1991)
The 185-nm photolysis and pyrolysis of the spirocyclopropane derivatives of the azoalkanes 2,3-diazatricyclo4,9>non-2-ene (1a), 4',5'-diazaspiro(cyclopropane-1,8'-tricyclo3,7>non-4'-ene) (1b), and 4',5'-diazadispiro(cyclopropane-1,2'-tricyclo3,7>non-4'-ene-8',1''-cyclopropane) (1c) and their denitrogenated hydrocarbon derivatives tricyclo2,7>heptane (2a), spiro(cyclopropane-1,3'-tricyclo2,7>heptane (2b), and dispiro(cyclopropane-1,3'-tricyclo2,7>heptane-6',1''-cyclopropane) (2c) were investigated.It was shownthat the 185-nm photochemical behavior of these substrates does not depend on the degree of spirocyclopropane substitution.As common products in the 185-nm photolysis of the azoalkanes 1a-c were obtained the tricycloalkanes 2a-c (major products), the norbornenes 3a-c, the vinylcyclopentenes 5a-c (minor products), and the exo-methylenecyclohexenes 6a-c (traces).In the case of the parent azoalkane 1a additionally bicyclohept-2-ene (4) and bicyclohept-2-ene (7a) were detected.The major products in the photolysis of the tricycloheptanes 2a-c were the vinylcyclopentenes 5a-c, but also the norbornenes 3a-c and the methylenecyclohexenes 6a-c were formed in considerable amounts.Although the norbornenes 3a-c and the bicycloheptene 4a are logical Wagner-Meerwein rearrangement products, attempts to trap the suspected radical-cationic and zwitterionic intermediates with CF3CH2OH failed.Efforts to generate the authentic radical-cationic species by means of photosensitized elctron transfer (PET) by using sensitizers such as cyanoarenes, quinones, and pyrylium salts were unproductive.Vibrationally excited bicyclohepta-2,7-diyls, generated by the pyrolyses of 2a-c, are not precursors to the norbornenes 3a-c because, instead of such rearrangement products, cyclobutane cleavage of the bicyclopentane moiety takes place to afford the isomeric vinylcyclopentenes 5'a-c.Carbene intermediates, produced either from the 1,3-diyl-type species through fragmentation or from the photodenitrogenation of diazoalkanes, which are generated by retro-cleavage of n,?* excited azoalkanes 1a-c, in turn obtained through internal conversion of higher excited states such as 1?,?*, 1n,?*, and Ry, are proposed as the most likely precursors to either the vinylcyclopentenes 5a-c or methylenecyclohexenes 6a-c, respectively.In violation of Kasha's rule, photochemistry directly from the higher states of the azoalkanes 1a-c competes with internal conversion to the lowest excited state, namely the n,?* state, as it was shown by the formation of norbornenes 3a-c.
THE TRANSITION METAL COMPLEX PROMOTED ISOMERIZATION OF trans-BICYCLOHEPT-3-ENE TO cis-BICYCLOHEPT-3-ENE
Gassman, Paul G.,Bonser, Steven M.
, p. 3431 - 3434 (1983)
An unprecedented isomerization of a trans-1,2-disubstituted cyclopropane to a cis-1,2-disubstituted cyclopropane has been achieved with both rhodium(I) and platinum(II) catalysts.
Synthese von Propellanen (n = 2,3,4)
Fuchs, Josef,Szeimies, Guenter
, p. 2517 - 2522 (2007/10/02)
A facile access to the parent propellanes 2, 3 and 4 is presented.Lithiation of methallyl alcohol with BuLi/TMEDA complex and reaction of the organometallic intermediate 8 with parformaldehyde, ethylene oxide, or oxetane affords the diols 9 which are converted via the dichlorides 10 into tetrahalides 11.The cyclization of 11 to the corresponding propellanes is effected with 2 equiv. of MeLi or BuLi via bromobicyclobutanes 12.As expected, 2 cannot be isolated; its formation is deduced from the structure of the consecutive products.Key Words: Small-ring propellanes / Bicyclobutane bridging
THE REDUCTION OF 2-VINYL-1,1-BIS(BROMOMETHYL)CYCLOPROPANE
Zefirov, N. S.,Kozhushkov, S. I.,Kuznetsova, T. S.,Sosonkin, I. M.,Domarev,A. M.,et al
, p. 1863 - 1873 (2007/10/02)
A study was carried out on the reduction of 2-vinyl-1,1-bis(bromomethyl)cyclopropane by various methods including electrochemical procedures.The major reaction pathways ential opening and expansion of the cyclopropane ring, while the product of the formation of a second three-membered ring, namely, vinylspiropentane, is formed in low yield.The probable radical mechanism for this reaction is discussed.
