Microwave irradiation in the presence of palladium acetate and traces of dimethylformamide allows the fast and efficient cyclodehydrogenation of diphenylamines into carbazoles. The scope of the microwave-assisted reaction is broader than that of the one using conventional conditions in that it allows the preparation of oxygenated carbazoles without apparent loss in yield. The applicability of the method to the preparation of carbazole alkaloids has been demonstrated by the development of a total synthesis of murrayafoline A, which proceeds in 50% overall yield from commercially available materials and is the shortest and most efficient route for the preparation of this alkaloid to date.
在有
醋酸钯和微量二甲基甲酰胺的存在下进行微波照射,可以快速高效地将
二苯胺环脱氢成卡巴唑。与传统条件下的反应相比,微波辅助反应的适用范围更广,因为它允许在产率几乎没有明显损失的情况下制备氧化卡巴唑。该方法在卡巴唑
生物碱的制备中的适用性已经通过murrayafoline A的总合成得到了证明,该合成从市售材料出发,整体产率达到50%,是迄今为止制备该
生物碱的最短和最高效的路线。