Addition of Organometallic Reagents to Chiral<i>N</i>‐Methoxylactams: Enantioselective Syntheses of Pyrrolidines and Piperidines
作者:Mascha Jäkel、Jianping Qu、Tobias Schnitzer、Günter Helmchen
DOI:10.1002/chem.201302735
日期:2013.12.2
Enantioselective iridium‐catalyzed allylic substitutions were used to prepare N‐allyl hydroxamic acid derivatives that were suitable for ring‐closing metathesis, giving N‐methoxylactams. Reactions of these derivatives with Grignard or organolithium compounds gave hemiaminals, which could be reduced diastereoselectively via acyliminium intermediates to give cis‐piperidines or cis‐pyrrolidines with substituents
用对映选择性的铱催化的烯丙基取代基制备适合于闭环易位的N-烯丙基异羟肟酸衍生物,得到N-甲氧基内酰胺。这些衍生物与格氏试剂或有机锂化合物的反应,得到hemiaminals,其可非对映选择性经由acyliminium中间体,得到降低顺-哌啶或顺-pyrrolidines与取代基在2,6-或2,5-位置处分别。此外,可以通过与氰化钾/ AcOH进行相应反应来合成具有季碳中心的化合物。该程序应用于生物碱(-)-209D和(+)-脯氨酸的合成。