531-45-3Relevant academic research and scientific papers
1,2,4,6-CYCLOHEPTATETRAENE: THE KEY INTERMEDIATE IN ARYLCARBENE INTERCONVERSIONS AND RELATED C7H6 REARRANGEMENTS
McMahon, Robert J.,Abelt, Christopher J.,Chapman, Orville L.,Johnson, Jeffery W.,Kreil, Curits L.,et al.
, p. 2456 - 2469 (2007/10/02)
Thermolysis or photolysis of phenyldiazomethane (2) produces phenylmethylene (3), which ring-expands to give 1,2,4,6-cycloheptatetraene (6).Spectroscopic and chemical evidence rule out bicyclo(4.1.0)hepta-2,4,6-triene (4), cycloheptatrienylidene (5), and bicyclo(3.2.0)hepta-1,3,6-triene (11) intermediates.The strained allene in cycloheptatetraene (6) exhibits infrared absorption at 1824 and 1816 cm-1.Deuterium substitution produces the expected 10-cm-1 shift in the allene absorption.Fluorine or chlorine substitution substantially enhances the allene absorption intensity.Deuterium labeling studies reveal that the intramolecular chemistry of cycloheptatetraene (6) involves reversible thermal or photochemical equilibriation with phenylmethylene (3).The intermolecular chemistry of 6 involves dimerization.At temperatures as low as 10 K, 6 forms a labile (2+2) dimer,7, which undergoes thermally allowed, electrocyclic ring opening to give heptafulvalene (8) upon warming to room temperature.The rearrangements of 7-acetoxynorbornadiene (9), 2-diazobicyclo(3.2.0)hepta-3,6-diene (31), and 8-diazobicyclo(2.2.2)octa-2,5-dien-7-one (33) all involve cycloheptatetraene (6) intermediates.
Bicyclofulvenes, XI, On the Question of Spiroconjugation in Spiro
Riemann, Achim,Hoffmann, Reinhard W.,Spanget-Larsen, Jens,Gleiter, Rolf
, p. 1000 - 1007 (2007/10/02)
The title compound 4 as well as the derivatives 5 and 6 have been prepared.The first band in the UV spectrum of 4 in n-heptane is blue-shifted by ca. 20 nm with respect to those of 5 and 6.Model calculations with the CNDO/S-CI method indicate that this hypsochromic shift as well as the bathochromic shift of the corresponding band of 2 relative to that of 3, cannot be explained by spiroconjugation.The thermolysis of 4 yields benzene, heptafulvalene (15), and fulveneallene (16).The latter products are probably derived from cycloheptatrienylidene (14) as an intermediate.
Carbene Reactions, XV. - Attempted Generation of Tricarbonylcycloheptatrienylidene Chromium
Hoffmann, Reinhard W.,Lotze, Marion,Reiffen, Manfred,Steinbach, Klaus
, p. 581 - 590 (2007/10/02)
Fluorodesilylation of trimethylsilyltropylium ion (5b) generated cycloheptatrienylidene (6), which could be trapped by dimethyl fumarate.In the absence of trapping agents 6 dimerized to heptafulvalene (8).The analogous treatment of tricarbonyl(trimethylsilyltropylium) chromium (4b) led to the dihydrodimer 13 of tricarbonylcycloheptatrienylidene chromium (3).
Carbene Reactions, XIV. - Generation of Cycloheptatrienylidene by Vapor Phase Thermolysis of C7H7-Acetates
Hoffmann, Reinhard W.,Loof, Ingo H.,Wentrup, Curt
, p. 1198 - 1206 (2007/10/02)
Gas phase thermolysis at 450 deg C of 7-acetoxynorbornadiene (1) or of 7-acetoxycycloheptatriene (2) yielded acetic acid and heptafulvalene (4) indicative of the intermediate formation of cycloheptatrienylidene (3).The latter rearranged to fulveneallene (8) on thermolysis at 600 deg C.The elimination of acetic acid could involve a tropylium/acetate-ion pair since ionic processes dominate in the similar elimination of acetic acid from the tricyclic acetate 20.
