The State Key Laboratory of Elemento-Organic Chemistry and Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), College of Chemistry, Nankai University , Tianjin 300071, P. R. China.
Org Lett. 2017 Oct 20;19(20):5637-5640. doi: 10.1021/acs.orglett.7b02800. Epub 2017 Oct 3.
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.
一种新型杂化 P-手性膦氧-膦配体催化的α,β-不饱和亚胺与烯丙基碳酸酯的高对映选择性和非对映选择性[4 + 1]环加成反应已经实现，该反应提供了具有丰富手性的多取代 2-吡咯啉，产率良好至优秀，对映选择性高达 99%ee。基于韩的方法，该催化剂分子中仅具有单一的 P(O)-手性，容易获得，并代表了一类新的手性膦有机催化剂。在可能的催化机制中，原位生成的鏻阳离子与极性手性 P═O 部分之间的分子内库仑相互作用可能发挥了积极作用。
