Development of Enantioselective Synthetic Routes to (−)-Kinamycin F and (−)-Lomaiviticin Aglycon
作者:Christina M. Woo、Shivajirao L. Gholap、Liang Lu、Miho Kaneko、Zhenwu Li、P. C. Ravikumar、Seth B. Herzon
DOI:10.1021/ja307497h
日期:2012.10.17
cyclization, and diazo transfer provided the advanced diazofluorene 63, which was elaborated to (-)-kinamycin F (9) in three steps. The diazofluorene 87 was converted to the C(2)-symmetric lomaiviticin aglycon precursor 91 by enoxysilane formation and oxidative dimerization with manganese tris(hexafluoroacetylacetonate) (94, 26%). The stereochemical outcome in the coupling is attributed to the steric
描述了 (-)-kinamycin F (9) 和 (-)-lomaiviticin 苷元 (6) 的对映选择性合成路线的开发。目标的重氮四氢苯并[b]芴(重氮芴)官能团是通过β-三甲基甲硅烷基甲基-α,β-不饱和酮(38)与氧化萘醌(19)的氟化物介导偶联、钯催化环化(39)来制备的。 →37),和重氮转移(37→53)。D环前体60和68分别由间甲酚和3-乙基苯酚制备。β-三甲基甲硅烷基甲基-α,β-不饱和酮 60 与胡桃酮衍生物 61 偶联、环化和重氮转移得到高级重氮芴 63,分三步将其精制为 (-)-kinamycin F (9)。通过形成烯氧基硅烷并与三(六氟乙酰丙酮)锰(94, 26%)氧化二聚,将重氮芴 87 转化为 C(2)-对称洛马维菌素苷元前体 91。偶联中的立体化学结果归因于87的异丙酮醇缩醛和中间体的接触离子配对产生的空间偏倚。将偶联产物91脱保护(叔丁基过氧化氢、