crystallographic analysis of the key intermediate, and revealed that eurotiumide A and B have cis and trans configurations at H3/H4 positions, which are the opposite relationship of the stereochemistry from the previous report, respectively. The absoluteconfigurations of them are also determined. These naturalproducts exhibited highly fluorescence in several solvents with large Stokes shifts involving the excited-state
已经描述了二氢异香豆素型天然产物、eurotiumide A 和 eurotiumide B 的不对称全合成和结构修正。这些全合成的关键特征是不对称 Shi 环氧化、区域和立体选择性环氧化物开放、C1 插入/内酯化级联反应,用于构建 4-甲氧基异色满-1-one 骨架。我们在关键中间体的 X 射线晶体学分析的基础上证实了eurotiumide A 和B 的结构和构型,并揭示eurotiumide A 和B 在H3/H4 位置具有顺式和反式构型,这与分别来自上一份报告的立体化学。还确定了它们的绝对构型。这些天然产物在几种具有大斯托克斯位移的溶剂中表现出高度荧光,涉及激发态分子内质子转移机制,这得到了时间依赖密度泛函理论的支持。Eurotiumide A 也在蜡状芽孢杆菌中发出荧光。