Double Regioselective Asymmetric C-Allylation of Isoxazolinones: Iridium-Catalyzed N-Allylation Followed by an Aza-Cope Rearrangement
作者:Stefan Rieckhoff、Jan Meisner、Johannes Kästner、Wolfgang Frey、René Peters
DOI:10.1002/anie.201710940
日期:2018.1.26
enantioselective C‐allylations of isoxazolinones. These occur with high regioselectivity in favor of the linear allylation products, although Ir phosphoramidite catalysts were used, which commonly results in branched isomers. Our studies suggest that this outcome is the result of a reaction cascade via an initial regio‐ and enantioselective N‐allylation to provide a branched allyl intermediate, followed
异恶唑啉酮是生物学上和合成上令人感兴趣的稠密官能化的杂环,长期以来,通过不对称催化不能以对映体富集的形式获得。除了对映选择性方法的不足之外,由于杂环内各种亲核中心的竞争,异恶唑啉酮的功能化经常受到区域选择性问题的困扰。我们报告了异恶唑啉酮的第一个区域和对映体选择性C-烯丙基化。尽管使用了Ir亚磷酰胺催化剂,通常以支链异构体的形式出现,但区域选择性高,有利于线性烯丙基化产物。我们的研究表明,这种结果是通过最初的区域和对映选择性N-烯丙基化反应提供一个分支的烯丙基中间体而进行的级联反应的结果,