95514-03-7Relevant articles and documents
Syntheses of Gymnothespirolignans B and C and Non-natural Isomer 9-Epi-gymnothespirolignan B
Ali, Ghada,Cuny, Gregory D.
supporting information, p. 10517 - 10525 (2021/07/31)
Syntheses of polycyclic spiro lignans gymnothespirolignans B and C as well as the unnatural isomer 9-epi-gymnothespirolignan B were accomplished using (R)-Roche ester and an appropriately substituted fluorenone. Key features of the convergent syntheses include coupling of the fluorenone and an iodo-alkene intermediate derived from (R)-Roche ester in the presence of the Lewis acid TiCl(OiPr)3, C9-O bond formation via an SN2 reaction with retention of stereochemistry, and diastereoselective hydrogenations of a common alkene intermediate guided by accessibility or positioning by the C8-methoxy.
Ring-closing metathesis approaches towards the total synthesis of rhizoxins
Altmann, Karl-Heinz,Liniger, Marc,Neuhaus, Christian M.
supporting information, (2020/10/18)
Efforts are described towards the total synthesis of the bacterial macrolide rhizoxin F, which is a potent tubulin assembly and cancer cell growth inhibitor. A significant amount of work was expanded on the construction of the rhizoxin core macrocycle by ring-closing olefin metathesis (RCM) between C(9) and C(10), either directly or by using relay substrates, but in no case was ringclosure achieved. Macrocycle formation was possible by ring-closing alkyne metathesis (RCAM) at the C(9)/C(10) site. The requisite diyne was obtained from advanced intermediates that had been prepared as part of the synthesis of the RCM substrates. While the direct conversion of the triple bond formed in the ring-closing step into the C(9)-C(10) E double bond of the rhizoxin macrocycle proved to be elusive, the corresponding Z isomer was accessible with high selectivity by reductive decomplexation of the biscobalt hexacarbonyl complex of the triple bond with ethylpiperidinium hypophosphite. Radical-induced double bond isomerization, full elaboration of the C(15) side chain, and directed epoxidation of the C(11)-C(12) double bond completed the total synthesis of rhizoxin F.
Polyoxygenated Tertiary Alcohols: A Kiyooka Approach
Lücke, Daniel,Kalesse, Markus
supporting information, p. 10080 - 10083 (2019/07/18)
A Kiyooka aldol approach for the stereoselective synthesis of tertiary alcohols is presented. This approach allows for the incorporation of different substituents at all three remaining positions at the chiral center bearing the tertiary alcohol. To demon