Catalytic Asymmetric Intermolecular Stetter Reaction of Heterocyclic Aldehydes with Nitroalkenes: Backbone Fluorination Improves Selectivity
作者:Daniel A. DiRocco、Kevin M. Oberg、Derek M. Dalton、Tomislav Rovis
DOI:10.1021/ja904375q
日期:2009.8.12
The catalytic asymmetric intermolecular Stetter reaction of heterocyclic aldehydes and nitroalkenes has been developed. We have identified a strong stereoelectronic effect on catalyst structure when a fluorine substituent is placed in the backbone. X-ray structure analysis provides evidence that hyperconjugative effects are responsible for a change in conformation in the azolium precatalyst. This new
已经开发了杂环醛和硝基烯烃的催化不对称分子间 Stetter 反应。当氟取代基放置在骨架中时,我们已经确定了对催化剂结构的强烈立体电子效应。X 射线结构分析提供的证据表明,超共轭效应是造成唑鎓预催化剂构象变化的原因。这种在主链中带有氟取代的新型 N-杂环卡宾前体可显着提高一系列底物的对映选择性。