Towards the Rubromycins: An Efficient Synthesis of a Suitable Isocoumarin Precursor, its Lactam Analogue, and Palladium-Catalyzed Couplings
作者:Malte Brasholz、Xiaosong Luan、Hans-Ulrich Reissig
DOI:10.1055/s-2005-918417
日期:——
6-Iodoisocoumarin 4 and its aza-analogue, 6-iodo-1-oxo-isoquinoline 29, were efficiently prepared from vanillin in seven and six steps, respectively. Key transformations in their syntheses were achieved by directed ortho-lithiation and variations of Horner-Wadsworth-Emmons reactions. Both 6-iodoisocoumarin 4 and its aza-analogue were designed for insertion into syntheses of rubromycin type target structures via palladium-catalyzed coupling reactions. For the isocoumarin subunit, this plan could be confirmed through Heck, Sonogashira, and Suzuki reactions of our building block with various substrates.
通过七个步骤和六个步骤,分别从香兰素中高效地制备出了 6-碘异香豆素 4 及其杂氮类似物 6-碘-1-氧代异喹啉 29。合成过程中的关键转化是通过定向原位硫化和霍纳-沃兹沃斯-艾蒙斯反应的变化实现的。6-iodoisocoumarin 4 及其氮杂类似物都被设计用于通过钯催化的偶联反应插入红霉素类目标结构的合成中。对于异香豆素亚基,这一计划可以通过我们的结构单元与各种底物的 Heck、Sonogashira 和 Suzuki 反应得到证实。