A palladium-catalyzed [4 + 4] cycloaddition reaction is described. A vinylallene having a pendant phenyl or vinyl substituent was treated with a catalytic amount of a palladium(O) complex to afford a symmetrical eight-membered carbocycle. The extended conjugation of the diene unit of an intermediate with the pendant unsaturated substituent is important for the [4 + 4] cycloaddition to occur.
本文描述了一种
钯催化的[4 + 4]环加成反应。用催化量的
钯(O)络合物处理带有苯基或
乙烯基取代基的
乙烯基烯烃,得到一个对称的八元碳环。中间体的二烯单元与悬挂的不饱和取代基的扩展共轭对发生[4 + 4]环加成反应非常重要。