The title compound 5 was produced by 185nmphotolysis of 8. The products of the 185nmphotolysis can be rationalized by the assumption of the two diradical intermediates 16 and 17. At a temperature between 150 and 20 °C 5 reacts with fumaronitrile 23 to give the adducts 7 and 26 in a ratio of about (5 : 1). The kinetic analysis of this reaction shows, that the adduct 7 is formed by 1,3 dipolar cycloaddition
Synthetic Photochemistry. XLVI. Cycloaddition of<i>exo</i>,<i>endo</i>-2,7-Bis(methoxycarbonyl)-11,12-dioxatetracyclo[6.2.1.1<sup>3,6</sup>.0<sup>2,7</sup>]dodeca-4,9-diene and Conjugated Enones and<i>p</i>-Quinones
作者:Guan Rong Tian、Akira Mori、Nobuo Kato、Hitoshi Takeshita
DOI:10.1246/bcsj.62.506
日期:1989.2
Photocycloaddition of exo,endo-2,7-bis(methoxycarbonyl)-11,12-dioxatetracyclo[6.2.1.13,6.02,7]dodeca-4,9-diene with conjugated enones and p-quinones occurred exclusively at the exo-addition moiety to give [2+2]cycloadducts. From cyclohexenone, all four possible photoadducts were obtained. A single photoadduct from cyclopentenone was a cis-transoid-cis isomer. Upon thermolysis, cyclobutene derivatives were formed from these photoadducts. An acid treatment of oxetane derivatives derived from photoadducts of p-quinones afforded Michael adducts instead of dienone–phenol rearrangement products.
4-Acetoxytricyclo[4.1.0.02,7]hept-4-en-3-one (), a valenceisomer of 2-acetoxytropone, was synthesized. Upon heating in pyridine at 150°C, rearranged into 1-acetoxybicyclo[3.2.0]hepta-3,6-dien-2-one (); the mechanism of which was examined by means of deuterium labeling experiments.
Thermolysis of tricyclo[4.1.0.02,7]hept-4-en-3-one constitutes an unusual bond reorganisation reaction in which the alkenic carbon atoms are responsible for the construction of the cyclobutene ring in the product, bicyclo[3.2.0]hepta-3,6-dien-2-one.
Pyrolysis and UV photoelectron spectroscopy of bicyclo[3.2.0]hept-6-en-2-one; preparation and detection of cyclohepta-2(Z),4(E)-dien-1-one
作者:Tom Bajorek、Nick H. Werstiuk
DOI:10.1039/b111602a
日期:2002.3.7
Flashvacuumpyrolysis of bicyclo[3.2.0]hept-6-en-2-one (1) in the source chamber of a UV photoelectron (PE) spectrometer using a CW CO2 laser as a directed heat source facilitated an electrocyclic ringexpansion to yield the transient species cyclohepta-2(Z),4(E)-dien-1-one (2), the PE spectrum of which was compared to that of an authentic sample of cyclohepta-2(Z),4(Z)-dien-1-one (4) and confirmed