Highly Stereoselective [4+2] Cycloaddition of Azlactones to β,γ-Unsaturated α-Ketoesters Catalyzed by an Axially Chiral Guanidine Base
作者:Masahiro Terada、Hiroyuki Nii
DOI:10.1002/chem.201003015
日期:2011.2.7
cycloaddition reaction of azlactones with β,γ‐unsaturated α‐ketoesters was demonstrated by taking advantage of the multiple reactive sites on the azlactone with the use of an axially chiral guanidine‐base catalyst. The most likely reaction pathway involves three consecutive steps to provide a facile access to α‐amino δ‐lactones with a sugar framework in a highly stereoselective manner (see scheme).
甜蜜的催化!利用轴向手性胍基催化剂,通过利用氮杂内酯上的多个反应位点,证明了氮杂内酯与β,γ-不饱和α-酮酸酯的对映体和非对映选择性环加成反应。最可能的反应途径包括三个连续的步骤,以高度立体选择性的方式(使用方案)轻松获得带有糖骨架的α-氨基δ-内酯。