in the naphthazarin and isocoumarin fragments facilitates the acid‐mediated spiroketalization step to afford the key densely functionalized spiroketal (see picture; EOM=ethoxymethyl) in the formal synthesis of (±)‐γ‐rubromycin. A novel regioselective allyloxylation/Claisen rearrangement of 2‐azido‐1,4‐naphthoquinone provides access to the highly oxygenated naphthazarin fragment.
平衡行为:
萘达
沙林和异
香豆素片段中电子因子的正确平衡促进了酸介导的螺酮缩合步骤,从而在(±)-γ-鲁布霉素的正式合成中提供了关键的致密功能化的螺
缩酮(参见图片;
EOM =乙氧基甲基)。新型的2-
叠氮基
1,4-萘醌的区域选择性烯丙氧基化/克莱森重排提供了进入高度氧化的
萘萘沙林片段的途径。