Synthesis of Angucyclines. 8. Biomimetic-Type Synthesis of Rabelomycin, Tetrangomycin, and Related Ring B Aromatic Angucyclinones
作者:Karsten Krohn、Norbert Böker、Ulrich Flörke、Christian Freund
DOI:10.1021/jo9622587
日期:1997.4.1
The angucyclinones with aromatic ring B (1a-c and 2a-c) are prepared in a biomimetic-type synthesis by two successive aldol cyclizations starting from the substituted naphthoquinones 12a-c. In both cyclization steps the C-H acidity of the potential nucleophilic centers determines the mode of cyclization under kinetically controlled conditions. The tetrahydroanthraquinones 13a-c/14a-c are hydroxylated
通过从取代的萘醌12a-c开始的两个连续的醛醇环化以仿生型合成制备具有芳香环B(1a-c和2a-c)的蒽环酮。在两个环化步骤中,潜在亲核中心的CH酸度决定了动力学控制条件下环化的模式。在用过量的NMO处理后,四氢蒽醌13a-c / 14a-c在C-4处羟基化为酚类蒽醌16a-c。