Synthesis of Seven-Membered Carbocyclic Rings via a Microwave-Assisted Tandem Oxyanionic 5-exodig Cyclization−Claisen Rearrangement Process
摘要:
Appropriately substituted 1-alkenyl-4-pentyn-l-ol systems, readily prepared from simple starting materials, serve as useful precursors to a number of substituted cyclohept-4-enone derivatives via a microwave-assisted tandem oxyanionic 5-exo cyclization/Claisen rearrangement sequence. The reactions involving terminally substituted 4-pentyn-1-ols were found to be highly stereoselective, with the a and beta groups in the final product showing a strong preference for the trans orientation.
Synthesis of Seven-Membered Carbocyclic Rings via a Microwave-Assisted Tandem Oxyanionic 5-<i>exo</i> <i>dig</i> Cyclization−Claisen Rearrangement Process
作者:Xin Li、Robert E. Kyne、Timo V. Ovaska
DOI:10.1021/jo0710432
日期:2007.8.1
Appropriately substituted 1-alkenyl-4-pentyn-l-ol systems, readily prepared from simple starting materials, serve as useful precursors to a number of substituted cyclohept-4-enone derivatives via a microwave-assisted tandem oxyanionic 5-exo cyclization/Claisen rearrangement sequence. The reactions involving terminally substituted 4-pentyn-1-ols were found to be highly stereoselective, with the a and beta groups in the final product showing a strong preference for the trans orientation.
Asymmetric Synthesis of Seven-Membered Carbocyclic Rings via a Sequential Oxyanionic 5-Exo-Dig Cyclization/Claisen Rearrangement Process. Total Synthesis of (−)-Frondosin B
作者:Timo V. Ovaska、Jonathan A. Sullivan、Sami I. Ovaska、Jacob B. Winegrad、Justin D. Fair
DOI:10.1021/ol900967j
日期:2009.6.18
the CBS methodology, were converted to optically active cycloheptenone derivatives with almost complete transfer of chirality via an efficient “one-pot”, cycloisomerization/Claisenrearrangement process. This methodology was directly applied to the expedient totalsynthesis of (−)-frondosin B.
适当取代的非外消旋烯丙醇很容易通过应用 CBS 方法从相应的烯酮制备,通过有效的“一锅”环异构化/克莱森重排过程,几乎完全转移手性,将其转化为光学活性环庚烯酮衍生物。该方法直接应用于 (-)-frondosin B 的权宜全合成。