An expeditious reaction sequence featuring a microwave-assisted tandem 5-exo cyclization-Claisen rearrangement process was used to assemble the A/B ring system of frondosin B. Completion of the target natural product was achieved in 38.2% yield over an eight-step linear sequence.
An expeditious reaction sequence featuring a microwave-assisted tandem 5-exo cyclization-Claisen rearrangement process was used to assemble the A/B ring system of frondosin B. Completion of the target natural product was achieved in 38.2% yield over an eight-step linear sequence.
Studies toward Frondosin A and Its Analogues. Formal Total Synthesis of (±)-Frondosin A
作者:Xin Li、Alec E. Keon、Jonathan A. Sullivan、Timo V. Ovaska
DOI:10.1021/ol8011343
日期:2008.8.7
Two reaction sequences commencing with different starting materials were successfully employed for the synthesis of frondosin A analogues, including (+/-)-frondosin A dimethyl ether. Construction of the bicyclo[5.4.0]undecane core in each case was achieved through an expedient microwave-assisted tandem 5-exo cyclization--Claisen rearrangement process.
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。
Total Synthesis of (±)-Frondosin B
作者:Xin Li、Timo V. Ovaska
DOI:10.1021/ol701633z
日期:2007.9.1
An expeditious reaction sequence featuring a microwave-assisted tandem 5-exo cyclization-Claisen rearrangement process was used to assemble the A/B ring system of frondosin B. Completion of the target natural product was achieved in 38.2% yield over an eight-step linear sequence.