Thermal Reaction of Highly Alkylated Azulenes with Dimethyl Acetylenedicarboxylate: HOMO(Azulene)vs. SHOMO(Azulene) Control in the Primary Thermal Addition Step
作者:Yi Chen、Roland W. Kunz、Peter Uebelhart、Roland H. Weber、Hans-J�Rgen Hansen
DOI:10.1002/hlca.19920750803
日期:1992.12.16
substituents. However, the main reaction channel of A is its retro-Diels-Alder reaction to the starting materials (azulene and ADM). The highly reversible Diels-Alder reaction of ADM to the five-membered ring of the azulenes is HOMO(azulene)/LUMO(ADM)-controlled, in contrast to the at 200° irreversible ADM addition to the seven-membered ring of the azulenes to yield the Diels-Alder products of type
在十氢化萘或四氢化萘乙炔二(ADM)高度烷基化的薁在180-200°的产率的反应,旁边的预期heptalene-和甘菊环-1,2-二羧酸酯,式的四环化合物的“反” - V和的三环化合物类型E(请参阅方案2-4和8-11)。'抗' -V型化合物代表主要的三环中间体A与ADM的Diels - Alder加合物。在某些情况下,E型三环化合物也经历了连续的Diels - Alder与ADM反应,得到类型“的四环化合物的抗‘ -或’ SYN ” - VI(参见方案2和8-11)。类型的三环化合物ë,即4和8,可逆地重新排列通过[1,5] -C转移到异构体的三环结构(CF。18和19,分别在方案6)已经在温度> 50℃。光化学4重排为对应的四环化合物20经由二π-甲烷反应。所观察到的heptalene-和甘菊环-1,2-二羧酸酯,以及“型的四环化合物的抗‘’ - V从初级三环中间体形成甲经由重排(he