17. endo Cycloadditions were strongly favoured with alkene dipolarophiles containing π bonds in substituents on the alkene unit. With N-substituted maleimides endo products were formed exclusively even when the N-substituent was tBu or adamantyl. Only with alkoxyvinyl ethers were exo-cycloadducts encountered. The mechanisms are discussed in conjunction with DFT calculations. An X-ray crystal structure
在反应
酞菁双
氰胺 1,3-偶极电子贫乏的单取代 烯烃 和
炔烃双极性亲和剂双
氰胺键合到未取代的碳上,得到1-取代的
吡咯并[2,1- a ]
酞嗪。对于富电子的双亲亲子体,其区域
化学是相反的,并且产物是2-取代的
吡咯并[2,1- a ]
酞嗪。发生了区域
化学的意外逆转
甲基丙烯酸甲酯,由于C–Me组的空间效应,主要产品是 2-外-甲基-2-内-甲氧基羰基-3,3-二
氰基-1,2,3,10b-
四氢吡咯并[2,1- a ]
酞嗪,17。内环加成受到强烈青睐烯烃在烯烃单元上的取代基中含有π键的亲二
氟体。用N-取代马来
酰亚胺 即使当N-取代基为t Bu或
金刚烷基时,也仅形成内生产物。只有被烷氧
乙烯基醚外-cycloadducts遇到。结合DFT计算讨论了这些机制。的X射线晶体结构报道于内切- ñ -叔丁基-3,3-二
氰基1,2,3,10b
四氢吡咯并[2,1-一个]
酞嗪-1,2-二羧
酰亚胺,25。