Dichloroketene−Chiral Olefin-Based Approach to Pyrrolizidines: Highly Stereocontrolled Synthesis of (+)-Amphorogynine A
作者:Caroline Roche、Philippe Delair、Andrew E. Greene
DOI:10.1021/ol034369f
日期:2003.5.1
[reaction: see text] A highlystereoselectiveroute to (+)-amphorogynine A, a novel pyrrolizidine recently isolated from the New Caledonian plant Amphorogynine spicata, has been realized. The key step in the approach is a diastereoselective [2 + 2] dichloroketene-chiral enolether cycloaddition (dr >or= 93:7) to access a dichlorocyclobutanone intermediate, which is converted into the alkaloid natural
[反应:见正文]已经实现了对(+)-两性腺嘌呤A的高度立体选择性的途径,这是最近从新喀里多尼亚植物Amphorogynine spicata中分离出来的一种新型吡咯烷并烷。该方法的关键步骤是非对映选择性的[2 + 2]二氯乙烯-手性烯醇醚环加成(dr> or = 93:7),以得到二氯环丁酮中间体,该中间体通过吡咯烷酮衍生物转化为生物碱天然产物。
Extending the Scope of the [2+2] Cycloaddition of Dichloroketene to Chiral Enol Ethers: Synthesis of (-)-Detoxinine
作者:Jean-François Poisson、Julien Ceccon、Andrew E. Greene
DOI:10.1055/s-2005-868515
日期:——
dichloroketene to a chiral enol ether, followed by Beckmann ring expansion and dechlorination, affords a potential intermediate for the synthesis of various natural products. The usefulness of this intermediate is first demonstrated by an asymmetric synthesis of (-)-detoxinine.