STUDIES ON TANDEM ASYMMETRIC DOUBLE MICHAEL ADDTION AND INTERNAL NUCLEOPHILIC SUBSTITUTION
Huang Min Chen Qinghua (Department of Chemistry, Beijing Normal University, 100875, Beijing, China)
The synthesis of a novel chiral synthon, 5 ( l menthyloxy) 3 bromo 2(5H) furanone (5a), and its application in asymmetric reaction are investigated. The unusual functionalized spiro cyclopropane derivatives containing four stereogenic centers 8a～d are obtained in good yields with d.e.≥98 % via tandem double Michael addition internal nucleophilic substitution of the novel chiral synthon, 5 l menthyloxy 3 bromo 2(5H) furanone 5a, with oxygen nucleophiles under mild conditions. The structure and configuration are identified on the basis of their analytical and spectroscopic ([ α ] 20 D,UV, IR, 1 HNMR, 13 CNMR, MS) and X ray crystallographic data.