Enantioselective Michael Addition of Cyclic β-Diones to α,β-Unsaturated Enones Catalyzed by Quinine-Based Organocatalysts
作者:Qingqing Wang、Wei Wang、Ling Ye、Xuejun Yang、Xinying Li、Zhigang Zhao、Xuefeng Li
DOI:10.3390/molecules22071096
日期:——
An enantioselective (52-98% ee) Michaeladdition between cyclic β-diones and α,β-unsaturated enones was established in the presence of quinine-based primary amine or squaramide. A variety of cinnamones were smoothly converted into the desired 3,4-dihydropyrans in moderate to high yields (63-99%). Chalcones were also suitable acceptors and gave rise to the expected adducts in satisfactory yields (31-99%)
Highly stereoselective synthesis of 2,3-dihydrofurans <i>via</i> a cascade Michael addition-alkylation process: a nitro group as the leaving group
作者:Yiran Mo、Siyang Liu、Yingying Liu、Ling Ye、Zhichuan Shi、Zhigang Zhao、Xuefeng Li
DOI:10.1039/c9cc01509d
日期:——
The Michael addition-alkylation process between gem-benzoyl-nitrostyrenes and 1,3-dicarbonyl compounds proceeded smoothly in the presence of a bifunctional squaramide, exclusively providing 2,3-dihydrofurans as trans-diastereomers in 33–92% isolated yields and excellent enantioselectivities (29–>99% ee).