Highly Enantioselective Synthesis of Spiro[cyclohexanone-oxindoles] and Spiro[cyclohexanone-pyrazolones] by Asymmetric Cascade [5+1] Double Michael Reactions
作者:Bin Wu、Jian Chen、Mei-Qiu Li、Jin-Xin Zhang、Xiao-Ping Xu、Shun-Jun Ji、Xing-Wang Wang
DOI:10.1002/ejoc.201101529
日期:2012.3
The asymmetric catalytic synthesis of naturally occurring and biologically active spiro compounds is a challenge for modern chemical methodology. Here we report the construction of spiro compounds through cascade [5+1] double Michael reactions between divinyl ketones and N-unprotectedoxindoles or N-phenyl-protected pyrazolones catalyzed by a combination of the easily available 9-amino-9-deoxy-epi-quinine
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