Bioinspired Total Synthesis and Human Proteasome Inhibitory Activity of (−)-Salinosporamide A, (−)-Homosalinosporamide A, and Derivatives Obtained via Organonucleophile Promoted Bis-cyclizations
作者:Henry Nguyen、Gil Ma、Tatiana Gladysheva、Trisha Fremgen、Daniel Romo
DOI:10.1021/jo101638r
日期:2011.1.7
bis-cyclization of a β-keto tertiary amide, which retains optical purity enabled by A1,3-strain rendering slow epimerization relative to the rate of bis-cyclization. Optimization studies of the key bis-cyclization, enabled through byproduct isolation and characterization, are described that ultimately allowed for a gram scale synthesis of a versatile bicyclic core structure with a high degree of stereoretention
受生物合成考虑的启发,描述了抗癌剂 (−)-salinosporamide A 及其衍生物(包括 (−)-homosalinosporamide)的简明、对映选择性合成的完整说明。合成策略的简洁性源于 β-酮叔酰胺的关键双环化,它保留了由 A 1,3菌株实现的光学纯度,从而相对于双环化速率呈现缓慢的差向异构化。描述了通过副产物分离和表征实现的关键双环化的优化研究,最终实现了具有高度立体保留的通用双环核心结构的克级合成。通过 Knochel 方法生成锌酸盐的优化程序通常用于合成 salino A 衍生物,导致侧链连接的显着改善和 salino A 的新型非对映异构体。合成证明了所述策略的多功能性设计的衍生物包括 (−)-homosalinosporamide A。还报道了使用酶法测定这些衍生物对人 20S 和 26S 蛋白酶体的抑制。所描述的盐A全合成提出了有趣的问题,即生物合成酶如何通过光