Synthesis of an N-protected 2-bromo-1 H-carbazole-1,4(9 H)-dione is reported for the first time. We took full advantage of the high polarization and electrophilic properties of this new compound to engage it in a regioselective hetero-Diels-Alder reaction. The resultant cycloadduct was next transformed to an isomer of the naturally occurring calothrixin B displaying a new 7 H-indolo[2,3- J]phenanthridine-7
首次报道了 N-保护的 2-溴-1 H-咔唑-1,4(9 H)-二酮的合成。我们充分利用了这种新化合物的高极化和亲电特性,使其参与了区域选择性的异狄尔斯-阿尔德反应。接下来将所得环加合物转化为天然存在的calothrixin B 的异构体,显示出新的 7 H-吲哚[2,3-J] 菲啶-7,13(8H)-二酮结构。