Parallel syntheses of the title swainsonine-related enantiomers 9 and 15 were achieved in five steps and in 55% overall yield via enantiomeric threose N-benzylimines 4 and 10, derived from L- and D-tartaric acid, respectively. A stereospecific 4+4 homologative procedure using 2-(trimethylsiloxy)furan (TMSOF), obtained from 2-furaldehyde, was employed to form the eight-carbon skeleton of the indolizidine triols and to install the proper chirality. Remarkably, the syntheses were completed by cyclizations of tetrahydroxypiperidine intermediates 8 and 14 to 9 and 15, respectively (ca. 90 %; PPh3, CCl4, Et3N in DMF at room temperature), without recourse to protecting groups.
Total Synthesis of L-(+)-Swainsonine and Other Indolizidine Azasugars from D-Glucose
作者:Mohammad Abrar Alam、Amit Kumar、Yashwant D. Vankar
DOI:10.1002/ejoc.200800649
日期:2008.10
A totalsynthesis of L-(+)-swainsonine, a potent and specific inhibitor of naringinase, along with the syntheses of six unnatural indolizidineazasugars are reported by starting fromD-glucose. L-(+)-Swainsonine was synthesized in 14 steps in 17 % overall yield. Further, two of the indolizidine analogues were found to be good glycosidase inhibitors at micromolar concentrations. In all of these syntheses
据报道,L-(+)-swainsonine(一种有效且特异性的柚皮苷酶抑制剂)的全合成,以及六种非天然吲哚里西啶氮杂糖的合成,均以 D-葡萄糖为起始原料。L-(+)-Swainsonine 分 14 步合成,总产率为 17%。此外,发现两种吲哚里西啶类似物在微摩尔浓度下是良好的糖苷酶抑制剂。在所有这些合成中,关键步骤是分子内 SN 2 反应。