作者:Peter Wipf、Yuntae Kim、Heike Jahn
DOI:10.1055/s-1995-4141
日期:1995.12
Starting with N-allyloxycarbonyl-protected 2,5-dimethoxyaniline, hypervalent iodine oxidation protocols and selective enone epoxidation provides the Streptomyces metabolite LL-C10037α in nine steps and 7-10% overall yield. In an asymmetric variant of this strategy, (R,R)-pentane-2,4-diol is used as a chiral acetalization agent. The resulting semiquinone spiroacetal, due to an ortho-acylamino substituent that restricts the 1,3-dioxane ring conformation, undergoes face-selective epoxidation and is further functionalized to give (-)-LL-C10037α in 94% ee. These pathways represent the first syntheses of the highly functionalized mC7N core of the manumycins and have been further extended toward the preparation of analogs for SAR studies of this class of antitumor antibiotics. Manumycins inhibit the farnesylation of Ras-protein by PFTase (protein farnesyltransferase).
以 N-烯丙氧基羰基保护的 2,5-二甲氧基苯胺为起点,通过高价碘氧化规程和选择性烯酮环氧化反应,九步即可得到链霉菌代谢物 LL-C10037δ,总收率为 7-10%。在这一策略的不对称变体中,(R,R)-戊烷-2,4-二醇被用作手性缩醛剂。由于正己胺基取代基限制了 1,3-二恶烷环的构象,由此产生的半醌螺缩醛进行了面选择性环氧化,并进一步官能化,得到了 (-)-LL-C10037 δ,ee 为 94%。这些方法首次合成了马诺霉素的高官能化 mC7N 核心,并进一步扩展到制备类似物,用于该类抗肿瘤抗生素的 SAR 研究。马努霉素能抑制 PFTase(蛋白法尼基转移酶)对 Ras 蛋白的法尼基化。