An Unusual Michael-Induced Skeletal Rearrangement of a Bicyclo[3.3.1]nonane Framework of Phloroglucinols to a Novel Bioactive Bicyclo[3.3.0]octane

Abstract

A novel skeletal rearrangement of bicyclo[3.3.1]nonane-2,4,9-trione (<b>16</b>) to an unprecedented highly functionalized bicyclo[3.3.0]octane system (<b>17</b>), induced by an intramolecular Michael addition, is presented. This novel framework was found to be similarly active to hyperforin (<b>1</b>), against PC-3 cell lines. A mechanistic study was examined in detail, proposing a number of cascade transformations. Also, reactivity of the Δ^7,10-double bond was examined under several conditions to explain the above results