- Total syntheses of all tri-oxygenated 16-phytoprostane classes: Via a common precursor constructed by oxidative cyclization and alkyl-alkyl coupling reactions as the key steps
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A unified strategy for the total synthesis of the methyl esters of all phytoprostane (PhytoP) classes bearing two ring-oxygen atoms based on an orthogonally protected common precursor is described. Racemic 16-F1t-, 16-E1-PhytoP and their C-16 epimers, which also occur as racemates in Nature, were successfully obtained. The first total synthesis of very sensitive 16-D1t-PhytoP succeeded, however, it quickly isomerized to more stable, but so far also unknown Δ13-16-D1t-PhytoP, which may serve as a more reliable biomarker for D-type PhytoP. The dioxygenated cyclopentane ring carrying the ω-chain with the oxygen functionality in the 16-position was approached by a radical oxidative cyclization mediated by ferrocenium hexafluorophosphate and TEMPO. The α-chain was introduced by a new copper-catalyzed alkyl-alkyl coupling of a 6-heptenyl Grignard reagent with a functionalized cyclopentylmethyl triflate.
- Smr?ek, Jakub,Pohl, Radek,Jahn, Ullrich
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supporting information
p. 9408 - 9414
(2017/11/22)
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- Precise isomerization polymerization of alkenylcyclohexanes: Stereoregular polymers containing six-membered rings along the polymer chain
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Pd and Ni diimine complexes catalyze the isomerization polymerization of alkenylcyclohexanes to afford polymers composed of alternating trans-cyclohexane-1,4-diyl rings and oligomethylene spacers with high selectivity. The melting points of the polymers vary from 130 to 226 °C depending on length of the oligomethylene spacer.
- Takeuchi, Daisuke
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supporting information; experimental part
p. 11106 - 11109
(2011/09/14)
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