- Divergent total synthesis of the lycopodium alkaloids huperzine A, huperzine B, and huperzine U
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Huperzine A, huperzine B, and huperzine U are congeners isolated from the Chinese herb Huperzia serrata (=Lycopodium serratum) in minuscule amounts. The most efficient total synthesis of huperzine A, the first asymmetric total syntheses of huperzine B, and the first total synthesis of huperzine U have been achieved efficiently in overall yields of 17%, 10%, and 9%, respectively, each spanning 10-13 steps from (R)-pulegone. The featured steps include palladium-catalyzed Buchwald-Hartwig coupling and Heck cyclization reactions and an Ir-catalyzed olefin isomerization reaction. This work has established the absolute configurations of huperzine B and huperzine U and revealed that natural huperzine A, huperzine B, and huperzine U possess the same set of absolute stereochemistries, thus providing support for the potential role of huperzine B and huperzine U in the biosynthesis of huperzine A.
- Ding, Rui,Fu, Jian-Guo,Xu, Guang-Qiang,Sun, Bing-Feng,Lin, Guo-Qiang
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- An efficient total synthesis of (-)-huperzine A
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The total synthesis of Lycopodium alkaloid (-)-huperzine A has been accomplished in 10 steps with 17% overall yield from commercially abundant (R)-pulegone. The synthetic route features an efficient synthesis of 4 via a Buchwald-Hartwig coupling reaction,
- Ding, Rui,Sun, Bing-Feng,Lin, Guo-Qiang
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supporting information
p. 4446 - 4449
(2012/10/29)
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- A new approach to the bicyclo[3.3.1]nonane framework of huperzine A-like molecules via palladium-catalyzed intramolecular γ-arylation
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In our synthetic studies toward huperzine A, a diastereoselective α′-alkylation of the α-amido-γ-methyl hexenone 4 was realized through a dianion intermediate which significantly enhanced the reactivity. Under the attempted Heck reaction conditions, an unexpected and unprecedented palladium-catalyzed intramolecular γ-arylation of 3 was observed, which generated 18 with bicyclo[3.3.1]nonane framework in satisfactory yield.
- Ding, Rui,Lu, Yunyu,Yao, Hequan,Sun, Bingfeng,Lin, Guoqiang
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scheme or table
p. 1097 - 1100
(2012/08/28)
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