14-ethenodibenzo[a,j]-anthracene-15,16-dicarboxylate (4b), and the investigation of their photoreactivity in solution and in the solid state is reported. The irradiation of 4a and 4b resulted in regioselective di-π-methane rearrangements to give semibullvalene products; however, the product distribution is inverted upon changing the reaction medium from solution to the solid state. In solution, an α-naphtho–vinyl
1,2-naphtho-annelated 桶烯衍
生物的合成,即二甲基-7,12-dihydro-7,12-ethenobenzo[a]anthracene-13,14-dicarboxylate (4a) 和二甲基-7,14-dihydro-7 ,14-ethenodibenzo[a,j]-anthracene-15,16-dicarboxylate (4b),以及它们在溶液和固态中的光反应性的研究。4a 和 4b 的辐照导致区域选择性二-π-
甲烷重排,得到半布瓦烯产物;然而,当反应介质从溶液变为固态时,产物分布会发生逆转。在溶液中,由于相应过渡态的选择性稳定,α-
萘酚-
乙烯基桥接作为初始光
化学步骤占主导地位,如基于相关双自由基中间体的结构所讨论的那样,