PENTACYCLIC SYSTEMS FOR INDOLE ALKALOIDS - FORMATION OF THE C-11-C-12 BOND - 2 SYNTHESES OF (/-)-ASPIDOSPERMIDINE
PENTACYCLIC SYSTEMS FOR INDOLE ALKALOIDS - FORMATION OF THE C-11-C-12 BOND - 2 SYNTHESES OF (/-)-ASPIDOSPERMIDINE
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DOI：
10.1021/ja00352a038
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发表时间：
1983-01-01
影响因子：
15
通讯作者：
HUFFMAN, JC
中科院分区：
文献类型：
--
作者：
GALLAGHER, T;MAGNUS, P;HUFFMAN, JC
四环酰胺10 [E= C 0 CH 2S（0）Ph]通过分子内Pummerer反应转化为五环酰胺11，具有Aspidosperma生物碱的基本骨架。将该方法应用于（±）-螺精脒3的合成，通过描述为环外氨基甲酸酯的路线进行，其中四环酰胺14 [E= COCH 2S（0）Ph]通过分子内Pummerer反应转化为五环酰胺15。15经脱硫、氢化铝锂还原得（±）-螺精脒3。第二种合成aspidospermidine的方法是在D环上取代E环上的酰胺羰基。该内环酰胺路线经由四环酰胺27进行，四环酰胺27在氧化成亚砜28后，接着进行分子内Pummerer反应，得到五环酰胺29。27和29的结构通过单晶X射线分析确认。29经脱硫得到30，用氢化铝锂还原得到（±）-aspidospermidine，3。
The tetracyclic amide 10 [E= C0CH2S (0) Ph] was converted through an intramolecular Pummerer reaction into the pentacyclic amide 11, having the basic frameworkof the Aspidosperma alkaloids. Application of this methodologyto the synthesis of (±)-aspidospermidine, 3, proceeded through a route described as an exocyclic carbamate, where the tetracyclic amide 14 [E= COCH2S (0) Ph] is converted into the pentacyclic amide 15 by an intramolecular Pummerer reaction. De-sulfurization of 15 to 16 and lithium aluminum hydride reduction gave (±)-aspidospermidine, 3. A second, alternative strategy for thesynthesis of aspidospermidine is described; it has the amide carbonyl in ring D, instead of ring E. This endocyclic amide route proceeds via the tetracyclic amide 27, which on oxidation to the sulfoxide 28, followed by intramolecular Pummerer reaction, gave the pentacyclic amide 29. The structures of 27 and 29 were confirmed by single-crystal X-ray analysis. Desulfurization of 29 gave 30, which was converted into (±)-aspidospermidine, 3, by reduction with lithium aluminum hydride.