Total Synthesis of Rhizoxin D, a Potent Antimitotic Agent from the Fungus <i>Rhizopus chinensi</i>s
作者:James D. White、Paul R. Blakemore、Neal J. Green、E. Bryan Hauser、Mark A. Holoboski、Linda E. Keown、Christine S. Nylund Kolz、Barton W. Phillips
DOI:10.1021/jo020537q
日期:2002.11.1
configuration at C5 of 2 through a stereoselective addition of the radical derived from dehalogenation of 21 at the beta carbon of the (Z)-alpha,beta-unsaturated ester. Aldehyde 29 was obtained from phenylthioacetal 24 and condensed with phosphorane 30, representing subunit B, in a Wittig reaction that gave the (E,E)-dienoate 31. This ester was converted to aldehyde 33 in preparation for coupling with
根霉菌素D(2)由分别代表C3-C9,C10-C13,C14-C19和C20-C27的四个亚基A,B,C和D合成。亚基A是通过碘代乙缩醛21的环化制备的,该碘代乙缩醛21通过在(Z)-α,β-不饱和酯的β碳上立体选择性地添加衍生自21的脱卤基团而将C5的构型设定为2。乙醛29从苯硫缩醛24中获得,并在代表Wittig的Wittig反应中与代表亚基B的磷烷30缩合。该酯被转化为醛33,以准备与亚基C偶联。由炔丙醇经六步获得甲基酮形式的甲基酮55。33的醇醛缩醛反应与用(+)-DIPCl制备的55的烯醇缩醛反应,得到具有(13S)-构型的期望的β-羟基酮56,与(13R)-非对映异构体的比率为17-20:1。还原成抗二醇57并作为TIPS醚58进行选择性保护后,将C15羟基酯化得到膦酸酯59。衍生自δ-内酯60的醛62的分子内Wadsworth-Emmons反应提供了大内酯63,该大内酯63在