Collective Synthesis of <i>Lycopodium</i> Alkaloids and Tautomer Locking Strategy for the Total Synthesis of (−)-Lycojapodine A
作者:Houhua Li、Xiaoming Wang、Benke Hong、Xiaoguang Lei
DOI:10.1021/jo3017555
日期:2013.2.1
The collective total synthesis of Lycopodium alkaloids (+)-fawcettimine (1), (+)-fawcettidine (2), (+)-alopecuridine (4), (−)-lycojapodine A (6), and (−)-8-deoxyserratinine (7) has been accomplished from a common precursor (15) based on a highly concise route inspired by the proposed biosynthesis of the fawcettimine- and serratinine-type alkaloids. An intramolecular C-alkylation enabled efficient installation
石蒜碱生物碱(+)-法西替明(1),(+ )-法西替丁(2),(+ )-草皮苷(4),(-)-lycojapodine A(6)和(-)-8的集体全合成-foxycerratinine(7)是由一种常见的前体(15)完成的,该方法基于fawcettimine型和serratinine型生物碱的拟议生物合成方法,基于高度简洁的路线而获得。分子内C-烷基化可以有效地安装具有挑战性的螺四价碳中心和氮杂-环壬烷环。三环骨架的制备以及氧杂-季中心的正确相对立体化学的建立是通过羟基定向的SmI 2介导的频哪醇偶联实现的。发现空前的串联跨环N-烷基化和Boc基团的去除实现了生物合成启发的过程,以提供所需的四环骨架。特别值得注意的是,独特而关键的互变异构体锁定策略可用于完成(-)-lycojapodine A的对映选择性全合成(6)。该合成过程的中心步骤是后期的高价碘氧化剂(IBX或Dess-Martin高碘烷)/