89757-40-4Relevant academic research and scientific papers
Photochemical Mechanism of the 1,3-Cycloaddition of Ethene to Benzene
Neumann, Frank,Jug, Karl
, p. 3511 - 3513 (1995)
The mechanism of the photochemical 1,3-cycloaddition of ethene to benzene was investigated by the semiempirical MO method SINDO1.The relevant first excited singlet potential energy hypersurface was studied, and intermediates and transition structures were optimized with limited configuration interaction (CI).Two different reaction pathways proposed by experimentalists were compared.From the calculated barriers, a mechanism which involves a prefulvene structure is favored, whereas a simultaneous 1,3-cycloaddition via an exciplex mechanism seems most unlikely.
Probing the nature and extent of stabilization within foiled carbenes: Homoallylic participation by a neighboring cyclopropane ring
Apeland, Ingrid Malene,K?hlig, Hanspeter,Lorbeer, Eberhard,Brinker, Udo H.
, p. 4879 - 4885 (2013/07/11)
Oxadiazoline 6 was synthesized to generate endo-tricyclo[3.2.1.0 2,4]octan-8-ylidene (3) by either photolysis or thermolysis. Diastereomer 6a thermally decomposed twice as fast as 6b. Carbene 3 was trapped stereoselectively by acrylonitrile and diethylamine in high yields. It behaved as a nucleophilic carbene with electron-poor alkenes, like acrylonitrile, but as an electrophile with very electron-rich species, such as diethylamine. However, when the reactions were performed in cyclohexane and cyclohexene, isomerization of 3 was favored. Replacement of the double bond in 7-norbornenylidene (1) by the single bond in the endo-fused cyclopropane unit of carbene 3 led to similar outcomes. Carbene 3 rightfully belongs to the family of foiled carbenes.
Stereochemical Course of the Denitrogenation of Optically Active 9,10-Dihydro-5,6-diazalumibullvalene to Optically Active 3,4-Dihydrosemibullvalene
Askani, Rainer,Andermann, Thomas,Mueller, Karl Michael
, p. 1927 - 1938 (2007/10/02)
Thermal decomposition of optical active diazalumibullvalene derivative (+)-6 gives optical active dihydrosemibullvalene (+)-5.The absolute configurations of optical active 6 and 5 were determined by correlation to tricyclooctanone 9 and 2-cyclopentene-1-a
Tricyclo2,8>oct-3-ene, -oct-4-ene, and -octane: Preparation and Thermolysis of the Hydro Derivatives of Octavalene
Christl, Manfred,Herzog, Clemens,Kemmer, Petra
, p. 3045 - 3058 (2007/10/02)
On treatment of 2,3,7,8-tetrabromobicyclooct-3-ene (7) with LiAlH4 an allylic rearrangement occurred with formation of tribromide 8, which was converted into 4-bromotricyclo2,8>oct-3-ene (9) by n-butyllithium.Sodium/tert-butyl alcohol and 9 reacted to give tricyclo2,8>oct-3-ene (4).Hydrogenation of 4 was achieved with diimine and afforded tricyclo2,8>octane (6) along with some bicyclooct-2-ene (10).Sodium iodide transformed 7 into the unrearranged iodide 12.Reduction of 7 with sodium in liquid ammonia led to bicycloocta-3,7-diene (11) in low yield.An allylic rearrangement took place when 7 was treated with AgNO3 to give nitrate 13.In another allylic rearrangement tribromide 14 was formed from 13 and LiAlH4.The reaction of 14 with n-butyllithium afforded 4-bromotricyclo2,8>oct-4-ene (15), and from 15 tricyclo2,8>oct-4-ene (5) was obtained by means of sodium/tert-butyl alcohol.By treatment of 4-bromooctavalene (16) with tert-butyllithium and subsequent hydrolysis, a new route to octavalene (1) was elaborated with virtually no formation of cyclooctatetraene as side product. - At 100 deg C 4 rearranged (t1/2 ca. 40 min) almost quantitatively to dihydrosemibullvalene (17).The decomposition of 5 at 200 deg C (t1/2 ca. 25 h) gave a complex mixture, in which only 11 has been identified.The saturated hydrocarbon 6 was converted virtually quantitatively into a 5.5 : 1 mixture of 3-methylenecycloheptene (18) and 1,3-cyclooctadiene (19) at 160 deg C (t1/2 ca. 8 h).Possible mechanisms of these rearrangements are discussed.
DENITROGENIERUNG VON OPTISCH AKTIVEM 9,10-DIHYDRO-5,6-DIAZALUMIBULLVALEN
Askani, R.,Hornykiewytsch, T.,Mueller, K. M.
, p. 5513 - 5514 (2007/10/02)
Thermal decomposition of optically active title compound 1 yields optically active 2.Denitrogenations of 6 and 7 lead to semibullvalenes 8 and 9 respectively as the major products.These results indicate a concerted nitrogen expulsion.
Synthesis and Reactions of Compounds of the 5,6-Diazalumibullvalene Series
Askani, Rainer,Hornykiewytsch, Theophil,Schwertfeger, Werner,Jansen, Martin
, p. 2154 - 2174 (2007/10/02)
The 9,10-diazasnoutane derivatives 3a and 16 can be rearranged to the 5,6-diazalumibullvalene derivatives 4a and 17 on treatment with acids. - The methyl-substituted diazasnoutane 16 is prepared by a new route.This compares favourably with an alternative
