Asymmetric synthesis of anthracyclinones: Regio- and stereoselective synthesis of (-)-7-deoxydaunomycinone through direct asymmetric introduction of an alkynyl unit into C9 ketone.
作者:Hiromichi FUJIOKA、Hirofumi YAMAMOTO、Hirokazu ANNOURA、Makoto MIYAZAKI、Yasuyuki KITA
DOI:10.1248/cpb.38.1872
日期:——
A New chiral AB-building block (5) for preparing optically active anthracyclinones was synthesized via compound 13a, which was obtained by the stereoselective nucleophilic addition of (trimethylsilyl)ethynylmagnesium chloride to the chiral 6-bromo-1-oxo-β-tetralone 1-acetal (12) derived from (-)-(2S, 3S)-1, 4-dimethoxy-2, 3-butanediol. Synthesis of (-)-7-deoxydaunomycinone [(-)-4] was achieved through a regiospecific condensation of 5 and 4-acetoxy-8-methoxyhomophthalic anhydride (18). The optical purity (100% ee) of (-)-4 was unambiguously confirmed by high performance liquid chromatographic analysis of (±)-4 and (-)-4 on a chiral column and also by proton nuclear magnetic resonance examination of the methylated compounds, (±)- and (-)-21, using the chiral shift reagent, tris[3-(trifruoromethylhydroxymethylene)-d-camphorato]europium(III) [Eu(tfc)3].
通过化合物 13a 合成了用于制备具有光学活性的蒽环类化合物的新型手性 AB 构建模块 (5),该化合物是通过将(三甲基硅基)乙炔基氯化镁立体选择性地加到从 (-)-(2S,3S)-1,4-二甲氧基-2,3-丁二醇得到的手性 6-溴-1-氧代-β-四氢萘酮 1-缩醛 (12) 上而得到的。通过 5 和 4-乙酰氧基-8-甲氧基间苯二甲酸酐(18)的区域特异性缩合,合成了(-)-7-脱氧去甲大诺霉素酮[(-)-4]。通过在手性色谱柱上对(±)-4和(-)-4进行高效液相色谱分析,以及使用手性转移试剂三[3-(三钌甲基羟基亚甲基)-d-樟脑]铕(III) [Eu(tfc)3]对甲基化化合物(±)-和(-)-21进行质子核磁共振检查,明确证实了(-)-4的光学纯度(100% ee)。