Asymmetric Aza-Diels–Alder Reactions of in Situ Generated β,β-Disubstituted α,β-Unsaturated N–H Ketimines Catalyzed by Chiral Phosphoric Acids
作者:Shunlong He、Huanchao Gu、Yu-Peng He、Xiaoyu Yang
DOI:10.1021/acs.orglett.0c01994
日期:2020.7.17
A novel asymmetric synthesis of dihydropyridinones with vicinal quaternary stereocenters has been realized by asymmetric aza-Diels–Alder reactions of 3-amido allylic alcohols with oxazolones enabled by chiral phosphoric acid catalysis. A series of aryl/alkyl- and alkyl/alkyl-disubstituted 3-amido allylic tertiary alcohols and 4-substituted oxazolones could be well tolerated in these reactions, producing
通过手性磷酸催化的3-酰胺基烯丙基醇与恶唑酮的不对称aza-Diels-Alder反应,已经实现了具有邻位四级立体中心的二氢吡啶酮的新型不对称合成。在这些反应中可以很好地耐受一系列芳基/烷基-和烷基/烷基-二取代的3-酰胺基烯丙基叔醇和4-取代的恶唑酮,从而产生具有优异的非对映选择性和高对映选择性的二氢吡啶并酮。进行了机理研究和对照实验以阐明反应机理,其中提出了构型定义的β,β-二取代α,β-不饱和NH酮亚胺作为关键中间体。