Synthesis of Natural and Unnatural Enantiomers of Goniofufurone and Its 7-Epimers from D-Glucose. Application of Palladium(II) - Catalyzed Oxycarbonylation of Unsaturated Polyols
作者:Tibor Gracza、Volker Jäger
DOI:10.1055/s-1994-25694
日期:——
Syntheses of 3,6-anhydro-2-deoxy-7-phenylglyconolactones (+)-1 and (+)-2 with D- and L-glycero-D-ido configuration, respectively, as well as of their enantiomers (-)-1 and (-)-2, from D-glucose are presented. The key steps are, (i) phenylmagnesium bromide additions to C1 or C5 of glucose-derived aldehydes 7 and 10, respectively, and (ii), palladium (II)-catalyzed oxycarbonylation of intermediate 1-phenyl-D- and -L-5-hexenitols 8/9 or 14/15. The syntheses proceed in 7 steps with 6% and 18% over-all yield for (+)-1/ (+)-2, and in 6 steps/ 11% and 16% for (-)-1/ (-)-2 ( from monoacetone glucose). The absolute configurations of goniofufurone (+)-1 and its 7-epimer (+)-2 thus established are in accord with those of all suggested biogenetic precursors and allowed, e.g., to propose the absolute configuration of (+)-goniopypyrone, a related cytotoxic, bicyclic styryllactone, and structures of potential biosynthetic intermediates not identified so far.
分别具有 D- 和 L-甘油-D-ido 构型的 3,6-脱水-2-脱氧-7-苯基乙醇内酯 (+)-1 和 (+)-2 及其对映体 (-) 的合成呈现了来自D-葡萄糖的-1和(-)-2。关键步骤是,(i) 苯基溴化镁分别加成到葡萄糖衍生的醛 7 和 10 的 C1 或 C5 上,以及 (ii) 钯 (II) 催化的中间体 1-苯基-D- 和 -L- 的氧羰基化5-己烯醇8/9或14/15。合成分 7 步进行,(+)-1/ (+)-2 的总产率为 6% 和 18%,(-)-1/ (-)- 合成分 6 步进行,总产率为 11% 和 16% 2(来自单丙酮葡萄糖)。由此建立的 goniofufurone (+)-1 及其 7-差向异构体 (+)-2 的绝对构型与所有建议的生物发生前体的绝对构型一致,并允许例如提出 (+)-goniopypyrone 的绝对构型,相关的细胞毒性、双环苯乙烯内酯和潜在生物合成中间体的结构迄今尚未确定。