Enantioselective [4 + 1]-Annulation of α,β-Unsaturated Imines with Allylic Carbonates Catalyzed by a Hybrid <i>P</i>-Chiral Phosphine Oxide–Phosphine
作者:Hanyuan Li、Jiesi Luo、Bojuan Li、Xizhen Yi、Zhengjie He
DOI:10.1021/acs.orglett.7b02800
日期:2017.10.20
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
Enantiopure Chiral Phosphines Bearing a Sulfinyl Group and their Application in Catalytic Enantiodivergent Synthesis of Polysubstituted Pyrrolines
作者:Hanyuan Li、Bojuan Li、Jianwei Zeng、Changzun Jiang、Zhengjie He
DOI:10.1002/adsc.202000105
日期:2020.7.16
In this work, a type of enantiopure chiral phosphines bearing a polar S=O sulfinyl group as the chiral unit in the molecule has been developed, which can be prepared in either enantiomeric form from commercially available materials by a three‐step route. The enantiopure chiral phosphines can catalyse enantiodivergent asymmetric [4+1] annulation reactions of α,β‐unsaturated imines and allylic carbonates
A pyridine-catalyzed ylide cyclization affording dihydrofurans and dihydropyrroles has been developed. In the presence of a catalytic amount of pyridine and Fe(Tcpp)Cl, α-ylidene-β-diketones and α,β-unsaturated imines react with diazoacetates providing dihydrofurans and dihydropyrroles respectively, in up to 96% yield with high diastereoselectivities.