First Total Syntheses of Aeruginosin 298-A and Aeruginosin 298-B, Based on a Stereocontrolled Route to the New Amino Acid 6-Hydroxyoctahydroindole-2-carboxylic Acid
作者:Nativitat Valls、Meritxell López-Canet、Mercè Vallribera、Josep Bonjoch
DOI:10.1002/1521-3765(20010817)7:16<3446::aid-chem3446>3.0.co;2-0
日期:2001.8.17
The first total syntheses of aeruginosin 298-A (1) and aeruginosin 298-B (3) are described. The syntheses of the alternative putative structures 2 and 4 were also accomplished. The key common strategic element is the stereo-controlled synthesis of (2S,3aS,6R,7aS)-6-hydroxyoctahydroindole-2-carboxylic acid (L-Choi, 5) from L-tyrosine. The synthesis of this new bicyclic alpha-amino acid, which is the core
描述了铜绿素298-A(1)和铜绿素298-B(3)的第一批合成。还完成了备选推定结构2和4的合成。关键的共同战略要素是从L-酪氨酸立体控制合成(2S,3aS,6R,7aS)-6-羟基八氢吲哚-2-羧酸(L-Choi,5)。作为铜绿素酶的核心,这种新的双环α-氨基酸的合成涉及桦木还原O-甲基-L-酪氨酸(6)和在酸性介质中将所得的二氢茴香醚7进行氨基环化,然后进行N-苄基化,得到非对映异构体12和13。用HCl-MeOH酸处理后,最后两个产生平衡混合物,其中内异构体13明显占优势。在(Boc)2O存在下加氢13得到16,经LS-Selectride还原后,可提供醇22(一种受保护的L-Choi)。22与D-亮氨酸,受保护的(R)-(4-羟苯基)乳酸和L-精氨酸片段的连续偶联,然后降低至精氨酸水平和脱保护的最终步骤完成了合成序列,产生了铜绿素酶298-A (1)。光谱比较显示,肽2具有先前针