Total Synthesis of (±)-Culmorin and (±)-Longiborneol: An Efficient Construction of Tricyclo[6.3.0.0<sup>3,9</sup>]undecan-10-one by Intramolecular Double Michael Addition
作者:Kiyosei Takasu、Sayaka Mizutani、Miho Noguchi、Kei Makita、Masataka Ihara
DOI:10.1021/jo000185s
日期:2000.6.1
TMSCl-NEt(3)-ZnCl(2) caused the intramolecular double Michael addition to afford tricyclo[6.3.0.0(3, 9)]undecan-10-one 12 in high yields with perfect stereoselectivity. The methodology was further elaborated to achieve efficient total syntheses of (+/-)-culmorin (1) and (+/-)-longiborneol (2). The common precursor 13 of them was obtained from 14 in 94% yield as a single isomer by the treatment with LHMDS. After
用LHMDS,TMSI-HMDS,Bu(2)OTf-HMDS处理4-[((5E)-6-甲氧羰基-5-己烯基] -3,4-二甲基-2-环戊烯-1-一(5),或TMSC1-NEt(3)-ZnCl(2)引起分子内双迈克尔加成,以高产率提供三环[6.3.0.0(3,9)] undecan-10-one 12,具有理想的立体选择性。进一步完善了该方法,以实现高效的(+/-)-culmorin(1)和(+/-)-longiborneol(2)的总合成。通过LHMDS处理,以单一异构体的形式从14以94%的产率获得它们的共同前体13。在通过水解将13转化为相应的酸24之后,使用S-(1-氧化-2-吡啶基)-1,1,3,3-四甲基硫代铀六氟磷酸盐(HOTT,27)进行氧化脱羧,然后进行桦木还原,立体选择性地提供(+/-)-culmorin(1)。通过标准转化由24个合成(+/-)-龙脑冰片(2)。另外,用