An organocatalytic asymmetric double Michael cascade reaction of unsaturated ketones and unsaturated pyrazolones: highly efficient synthesis of spiropyrazolone derivatives
作者:Jinyan Liang、Qiao Chen、Luping Liu、Xianxing Jiang、Rui Wang
DOI:10.1039/c2ob27095a
日期:——
The first organocatalytic double Michael cascadereaction between unsaturated ketones and unsaturatedpyrazolones has been developed which provides spiropyrazolone core structures containing two interval or three consecutive stereogenic centers with excellent diastereo- (>20 : 1) and enantioselectivities (up to 99% ee). Moreover, a pair of enantiomers 5 and 5′ can be achieved via different catalysts