Organo-catalyzed asymmetric cascade annulations reaction for the construction of bi-spirocyclic pyrazolone and oxindole derivatives

Bing-Bing Sun ^a, Jun-Bo Chen ^a, Jun-Qi Zhang ^a, Xiao-Peng Yang ^a, Hao-Peng Lv ^a, Zheng Wang^*b（王正）and Xing-Wang Wang ^*a（王兴旺）

^aKey Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science Soochow University, Suzhou 215123, China

^bState Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China

Org. Chem. Front., 2020, 7, 796--809

A bifunctional organocatalyst catalyzed tandem annulation reaction between β,γ-unsaturated α-ketoesters with α-arylidene pyrazolinones was reported. The tandem Michael–aldol process allows access to optically active bi-spirocyclic pyrazolone and oxindole compounds in high yields with good to excellent enantioselectivity and diastereoselectivity. The resulting bi-spirocyclic compounds possess highly dense functionalized substituents, two all-carbon spiro quaternary stereocenters and one hemiketal stereogenic centers.

链接：https://pubs.rsc.org/en/content/articlelanding/2020/qo/d0qo00001a#!divAbstract