Stereocontrolled Synthesis of the Fully Glycosylated Monomeric Unit of Lomaiviticin A
作者:Zhi Xu、Mikaela DiBello、Zechun Wang、John A. Rose、Lei Chen、Xin Li、Seth B. Herzon
DOI:10.1021/jacs.2c07631
日期:2022.9.7
We describe a stereocontrolled synthesis of 3, the fully glycosylated monomeric unit of the dimeric cytotoxic bacterial metabolite (−)-lomaiviticin A (2). A novel strategy involving convergent, site- and stereoselective coupling of the β,γ-unsaturated ketone 6 and the naphthyl bromide 7 (92%, 15:1 diastereomeric ratio (dr)), followed by radical-based annulation and silyl ether cleavage, provided the
我们描述了3的立体控制合成,即二聚细胞毒性细菌代谢物 (-)-lomaiviticin A ( 2 ) 的完全糖基化单体单元。一种涉及 β,γ-不饱和酮6和萘基溴化物7(92%,15:1 非对映异构体比 (dr))的收敛、位点和立体选择性偶联的新策略,然后是基于自由基的环化和甲硅烷基醚裂解,提供了四环5(总共 57%),它包含3的苷元的碳骨架。β-连接的 2,4,6-trideoxy-4-aminoglycoside l使用改良的 Koenigs-Knorr 糖基化,以 73% 的产率安装 -pyrrolosamine,β:α 选择性为 15:1。重氮取代基通过直接重氮转移引入富电子苯并茚 ( 4 → 27 )。α-连接的 2,6-二脱氧糖苷l-夹竹桃糖是通过金催化活化邻炔基糖基苯甲酸酯(75%,>20:1 α:β 选择性)引入的。然后,精心编排的残局序列提供了对3的有效访问。细胞活力研究表明,单体3在浓度高达