Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr (Germany).
Angew Chem Int Ed Engl. 2015 May 18;54(21):6241-5. doi: 10.1002/anie.201501608. Epub 2015 Apr 13.
Countless natural products of polyketide origin have an E-configured 2-methyl-but-2-en-1-ol substructure. An unconventional entry into this important motif was developed as part of a concise total synthesis of 5,6-dihydrocineromycin B. The choice of this particular target was inspired by a recent study, which suggested that the cineromycin family of antibiotics might have overlooked lead qualities, although our biodata do not necessarily support this view. The new approach consists of a sequence of alkyne metathesis followed by a hydroxy-directed trans-hydrostannation and a largely unprecedented methyl-Stille coupling. The excellent yield and remarkable selectivity with which the signature trisubstituted alkene site of the target was procured is noteworthy considering the rather poor outcome of a classical ring-closing metathesis reaction. Moreover, the unorthodox ruthenium-catalyzed trans-hydrostannation is shown to be a versatile handle for diversity-oriented synthesis.
无数聚酮类天然产物都具有 E 构型的 2-甲基-2-丁烯-1-醇结构。在完成 5,6-二氢辛可宁霉素 B 的简洁全合成过程中,我们开发了一种非常规的方法来构建这个重要的结构基序。选择这个特定的目标是受到最近一项研究的启发,该研究表明辛可宁类抗生素可能被忽视了具有先导品质,尽管我们的生物数据并不一定支持这种观点。这种新方法包括一系列炔烃复分解反应,随后是羟基导向的反氢锡化反应和一个在很大程度上前所未有的甲基-Steill 偶联反应。考虑到经典的闭环复分解反应的结果相当差,目标物的标志性三取代烯烃位点以优异的收率和显著的选择性得到是值得注意的。此外,非传统的钌催化反氢锡化反应被证明是用于多样性导向合成的多功能反应试剂。