Decarboxylative Grob-Type Fragmentations in the Synthesis of Trisubstituted<i>Z</i> Olefins: Application to Peloruside A, Discodermolide, and Epothilone D
作者:Kathrin Prantz、Johann Mulzer
DOI:10.1002/anie.200901740
日期:2009.6.22
elimination: A new method for the synthesis of methyl‐branched trisubstituted Z olefins, a structural motif in many polyketides with anticancer activity, relies on an −OH‐induced decarboxylative Grob‐type fragmentation (see scheme; Ms=mesyl). The starting materials are β‐mesyloxy lactones with a quaternary α center, which are prepared by aldol reactions in a diastereo‐ and enantioselective manner.
判别消除:为甲基支化的三取代的合成的新方法Ž 烯烃,具有抗癌活性的许多聚酮化合物的结构基序,依赖于- OH诱导脱羧格罗型片段化(参见方案; MS =甲磺酰基)。起始原料是具有季α中心的β-甲氧基内酯,它们是通过非对映和对映选择性的醛醇缩合反应制备的。
Synthesis of (<i>Z</i>)-Trisubstituted Olefins by Decarboxylative Grob-Type Fragmentations: Epothilone D, Discodermolide, and Peloruside A
作者:Kathrin Prantz、Johann Mulzer
DOI:10.1002/chem.200901567
日期:2010.1.11
induced Grob‐type fragmentation as an easy access to trisubstituted olefins. In our case, β‐mesyloxy δ‐lactones with three stereogenic centers were chosen whose fragmentation underlies a high stereoelectronic control. Major challenges in the syntheses were the installation of quaternary stereocenters, achieved by enzymatic desymmetrization of meso‐diesters and by aluminium‐promoted stereoselective rearrangement