A new short and efficient synthesis of calothrixin B is reported. The key reaction is a hetero-Diels-Alder reaction between 3-bromo-9H-carbazole-1,4-dione and a ‘push-pull’ 2-aza-1,3-diene.
报告了一种新的简短高效的卡洛曲辛 B 合成方法。关键反应是 3-溴-9H-咔唑-1,4-二酮与 2-氮杂-1,3-二烯之间的异狄尔斯-阿尔德反应。
A convergent synthesis of the naturally occurring alkaloid Calothrixin B is presented, which used a regioselective hetero-Diels−Alder reaction between a “push−pull” 2-aza-diene and a N-protected 3-bromo-9H-carbazole-1,4-dione to construct the five-ring skeleton of the molecule. Protection of the indole motif with a benzyl group was unattractive for delivery of sufficient target material because the