Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, PR China.
J Am Chem Soc. 2010 Aug 11;132(31):10650-1. doi: 10.1021/ja1046928.
A new type of C(2)-symmetric chiral bisguanidine was designed as a highly efficient catalyst in the inverse-electron-demand hetero-Diels-Alder reaction of chalcones with azlactones for the first time. A wide variety of gamma,delta-unsaturated delta-lactone derivatives with alpha-quaternary-beta-tertiary stereocenters were obtained in high yields (up to 88%) with excellent enantioselectivities (up to 99% ee). Hydrogen bonds were considered to be crucial for the activation and stereoinduction of the reaction. In all cases, the major was HDA adducts, which were obtained as a single diastereomer along with little amount of Michael addition products.
首次设计了一种新型 C(2)对称手性双胍，作为高效催化剂，用于查尔酮与氮杂内酯的逆电子需求杂 Diels-Alder 反应。各种γ,δ-不饱和δ-内酰胺衍生物具有α-季-β-叔立体中心，产率高（高达 88%），对映选择性好（高达 99%ee）。氢键被认为是反应激活和立体诱导的关键。在所有情况下，主要的是 HDA 加合物，它们作为单一非对映异构体获得，同时还有少量的迈克尔加成产物。
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