Synthesis of functionalized spiro-cyclopropane bis-lactones containing multiple chiral centers

In this paper, the unusual spiro - cyclopropane bis - lactones containing f our stereogenic centers 4a similar to 4d were obtained in 25% similar to 48 % yields with d. e. greater than or equal to 98% via tandem double Michael addition/internal nucleophilic substitution of the novel chiral synthon, 5- l-menthloxy-3-bromo-2-(5H)-furanone 1, with nitrogen nucleophiles under mil d conditions. The structure and configuration were established on the basis of their analytical and spectroscopic ([alpha](D)(20), UV, IR, H-1 NMR, C- 13 NMR, MS and X - ray crystallographic) data. These results provide a valu able synthetic route to some complex molecules containing spiro-cyclopropan e skeleton with multiple chiral centers.