Enantioselective [4 + 1]-Annulation of α,β-Unsaturated Imines with Allylic Carbonates Catalyzed by a Hybrid P -Chiral Phosphine Oxide–Phosphine

作者：Hanyuan Li, Jiesi Luo, Bojuan Li, Xizhen Yi, Zhengjie He · 发表于：Organic Letters · 年份：2017 · DOI：10.1021/acs.orglett.7b02800 · 被引用次数：76 · 研究领域：Asymmetric Hydrogenation and Catalysis、Asymmetric Synthesis and Catalysis、Synthetic Organic Chemistry Methods

A highly enantio- and diastereoselective [4 + 1]-annulation reaction between α,β-unsaturated imines and allylic carbonates has been realized under the catalysis of a novel hybrid P-chiral phosphine oxide-phosphine, providing enantioenriched polysubstituted 2-pyrrolines in good to excellent yields and up to 99% ee. Based on Han's methods, the catalyst featuring a sole P(O)-chirality in the molecule is readily accessible and represents a class of new chiral phosphine organocatalysts. In the plausible catalytic mechanism, an intramolecular Coulombic interaction between the in situ generated phosphonium cation and polar chiral P═O moiety may play a positive role.