Protecting-Group-Free Total Synthesis of Isoquinoline Alkaloids by Nickel-Catalyzed Annulation of<i>o</i>-Halobenzaldimine with an Alkyne as the Key Step
作者:Rajendra Prasad Korivi、Chien-Hong Cheng
DOI:10.1002/chem.200902275
日期:2010.1.4
3]dioxol‐5‐yl substitution at the C3 atom and a (CH2)2OH group at the C4 atom. Later, oxidation of the alcohol group in 5 b–d to the aldehyde moiety followed by acid‐catalyzed cyclization and dehydration completes the total syntheses to give oxyavicine, oxynitidine, and oxysanguinarine in 67, 65, and 60 % yields, respectively. The synthesis requires four steps from o‐bromobenzaldehyde derivatives.
描述了一种有效的短总合成苯并[ c ]菲啶生物碱,包括氧鸟嘌呤,氧硝啶和氧桑桂碱。因此,Ñ甲基ö -bromobenzaldimines 1b中- d经历环化区域选择性与4-(苯并[ d ] [1,3]二氧杂环戊烯-5-基)丁-3-炔-1-醇(图2b中) [Ni(cod)2 ]的存在(cod = 1,5-环辛二烯)。原位氧化生成的异喹啉鎓盐可得到异喹啉酮衍生物5 b - d,在C 3原子处有苯并[ d ] [1,3]二氧杂-5-基取代,且(CH 2)2C 4原子上的OH基团。随后,在5 b - d内将醇基氧化为醛部分,然后进行酸催化的环化和脱水,完成了全部合成反应,分别以67%,65%和60%的收率得到了氧鸟嘌呤,氧亚硝胺和氧山桂碱。从邻-溴苯甲醛衍生物的合成需要四个步骤。本文还讨论了这些生物碱向该家族中其他生物碱的转化。