Synthesis of a Nitro Analogue of Plakoric Acid



Synthesis of a nitro analogue of plakoric acid is presented. The peroxy bond was incorporated into the substrate structure through a boron trifluoride etherate catalyzed methoxy-hydroperoxy group partial exchange reaction in diethyl ether with urea-hydrogen peroxide complex (UHP, a commercially available solid reagent) as the source of the hydrogen peroxide. Under the given conditions, only one of the two methoxyl groups underwent the MeO–OOH exchange and the resulting hydroperoxy hemiketal proceeded directly to the end product through an intramolecular Michael addition of the hydroperoxyl group to the nitro group activated carbon-carbon double bond.