[reaction: see text]. Dynamic gas-phase thermoisomerization (DGPTI) of medium- and large-ring 3-vinylcycloalkanones at 600-630 degrees C produces isomeric gamma,delta-unsaturated cycloalkanones expanded by two carbon atoms. A reaction mechanism involving an open-chain diradical intermediate, followed by intramolecular recombination under insertion of the vinyl group is proposed. Substituents on the
[反应:请参见文字]。在600-630摄氏度下,中环和大环3-
乙烯基环烷酮的动态气相热异构化(DG
PTI)产生被两个碳原子膨胀的异构体γ,δ-不饱和环烷酮。提出了一种反应机理,包括开链双自由基中间体,然后在
乙烯基的插入下进行分子内
重组。
乙烯基部分上的取代基分别作为相应的β和γ取代基被局部特异性转移到扩环的酮上。可通过3-
乙炔基
环十二烷酮的DG
PTI(540℃)完成非常规环状烯的制备。