1,3-Dipolar cycloaddition of nitrilimines 3 with N-benzyl maleimide 4 has provided 5-benzyl-1-(2′,4′-dibromophenyl)-3-(4″-substituted phenyl)-3a,4,6,6a-tetrahydro-1H,5H-pyrrolo[3,4-c]pyrazole-4,6-dione derivatives 5 in excellent yield as the only isomer through a concerted pathway.
硝基
亚胺 3 与 N-苄基马来
酰亚胺 4 的 1,3-二极环加成反应通过协同途径得到了 5-苄基-1-(2′,4′-二
溴苯基)-3-(4″-取代苯基)-3a,4,6,6a-四氢-1H,5H-
吡咯并[3,4-c]
吡唑-4,6-二酮衍
生物 5,这是唯一的异构体,收率极高。