A detailed account is given of the first chiral synthesis of the Ophiorrhiza alkaloid ophiorrhizine [(-)-1]. The synthesis was started by coupling the lactim ether (+)-4, readily available from cincholoipon ethyl ester [(+)-3], with 6-benzyloxy-3-chloroacetylindole (6) to form the lactam ketone (+)-8 and proceeded through the intermediates (+)-9, (+)-10, 11, (-)-12, (-)-13, 14, (-)-15, and (-)-16. The identity of synthetic (-)-1·H2O with natural ophiorrhizine unequivocally established the absolute stereochemistry of this alkaloid.
本文详细介绍了首次手性合成麦冬草
生物碱麦冬草素[(-)-1]的过程。合成的第一步是将内酰胺醚 (+)-4 与 6-苄氧基-3-
氯乙酰
吲哚 (6) 偶联,形成内酰胺酮 (+)-8,并通过中间体 (+)-9、(+)-10、11、(-)-12、(-)-13、14、(-)-15 和 (-)-16 继续进行。合成 (-)-1-
H2O 与天然
麦角碱的同一性明确地确定了这种
生物碱的绝对立体
化学结构。