The Diels–Alder reaction of semisquaric chloride 5 with 1-(alk-1-enyl)naphthalenes, 2-(alk-1-enyl)naphthalenes and 9-vinylphenanthrene is used to prepare dihydrocyclobuta[c]phenanthrene-1,2-diones 8a–c, dihydrocyclobuta[a]phenanthrene-1,2-diones 12a–c, and dihydrocyclobuta[a]triphenylene-11,12-dione 18, respectively. Treatment of the dihydrocyclobutaarenediones with bromine effects aromatization and opens up a route for the synthesis of cyclobuta[c]phenanthrene-1,2-diones 9a–c, cyclobuta[a]phenanthrene-1,2-diones 13a–c and cyclobuta[a]triphenylene-11,12-dione 19. The range of Diels–Alder reactions with semisquaric chloride 5 is extended to the use of 4-(prop-1-enyl)-1,2-dihydronaphthalene 14. Tetrahydrocyclobuta[a]phenanthrene-1,2-dione 15 is obtained in 69% yield, which can be oxidized, stepwise or at once, to give cyclobuta[a]phenanthrene-1,2-dione 13b in good yields.
                                    半方
氯化物5与1-(烷基-1-烯基)
萘、2-(烷基-1-烯基)
萘和
9-乙烯基菲的Diels-Alder反应用于制备二氢环丁[c]
菲-1,2-二酮分别为8a-c、二氢环丁[a]
菲-1,2-二酮12a-c和二氢环丁[a]苯并
菲-11,12-二酮18。用
溴处理二氢环丁芳二酮可实现芳构化,并开辟了一条合成环丁[c]
菲-1,2-二酮 9a–c、环丁[a]
菲-1,2-二酮 13a–c 和环丁[a]的路线。 ]苯并
菲-11,12-二酮 19. 与半方
氯化物 5 的狄尔斯-阿尔德反应范围扩展到使用 4-(丙-1-烯基)-
1,2-二氢萘 14. 四氢环丁[a]
菲-得到1,2-二酮15,收率69%,可以将其逐步或立即氧化,以良好的收率得到环丁[a]
菲-1,2-二酮13b。