Total Syntheses of Lycopodium Alkaloids (+)-Fawcettimine, (+)-Fawcettidine, and (−)-8-Deoxyserratinine
作者:Houhua Li、Xiaoming Wang、Xiaoguang Lei
DOI:10.1002/anie.201106753
日期:2012.1.9
A shared story: Three fawcettimine‐ and serratinine‐type Lycopodiumalkaloids are prepared from a common tetracyclic spirodiketone intermediate in concise total syntheses (see scheme). The intermediate was constructed by a remarkable biosynthesis‐inspired transannular NC bond formation to the spiro‐configured carbon center and a hydroxy‐directed pinacol coupling promoted by SmI2.
Application of the Helquist Annulation in <i>Lycopodium</i> Alkaloid Synthesis: Unified Total Syntheses of (−)-8-Deoxyserratinine, (+)-Fawcettimine, and (+)-Lycoflexine
total synthesis of the Lycopodium alkaloids (−)-8-deoxyserratinine (7), (+)-fawcettimine (1), and (+)-lycoflexine (4) is detailed. The key features include a highly efficient Helquist annulation to assemble the cis-fused 6/5 bicycle, facile construction of the aza nine-membered ring system employing double N-alkylation strategy, providing access to the common tricyclic skeleton, asymmetric Shi epoxidation
The first enantioselective total synthesis of (−)-8-deoxyserratinine has been achieved in 15 steps fromenone 4 with 7% overall yield. The key features include a highly efficient Helquist annulation to furnish the cis-fused 6/5 bicycle, facile construction of the aza nine-membered ring system employing double N-alkylation strategy, as well as asymmetric Shi epoxidation, delivering the desired β-epoxide
Redox Divergent Synthesis of Fawcettimine-Type<i>Lycopodium</i>Alkaloids
作者:Hisaaki Zaimoku、Tsuyoshi Taniguchi
DOI:10.1002/chem.201403163
日期:2014.7.28
A new approach for synthesis of fawcettimine‐type Lycopodium alkaloids is described. A divergent strategy was achieved by applying stereoselective Diels–Alder reaction followed by redox‐controlled elaboration. Eventually, (−)‐8‐deoxyserratinine, (+)‐fawcettimine, (−)‐lycopoclavamine‐A, (−)‐serratine, (−)‐lycopoclavamine‐B and (−)‐serratanidine were successfully accessed.
Divergent and Efficient Syntheses of the<i>Lycopodium</i>Alkaloids (−)-Lycojaponicumin C, (−)-8-Deoxyserratinine, (+)-Fawcettimine, and (+)-Fawcettidine
Four from one: The four title alkaloids (structures shown in blue box) have been synthesized by using a common versatile intermediate with a 6/5/5 tricyclic skeleton. This tricyclic intermediate could be easily assembled by using an intramolecular carbene addition/cyclization and a Dieckmann condensation/Tsuji–Trost allylation as key steps.