DBU/O2-Mediated Oxidation of Dienones.

Herein, we describe a DBU/O2-promoted novel method for oxidation of dienones to 2,6-dione derivatives. The reaction involves treatment of a dienone with DBU in acetonitrile employing molecular oxygen as the oxidant. Metal free conditions and an eco-friendly reagent are the striking features of this protocol. This transformation proceeds through a peroxide intermediate that upon Kornblum-DeLaMare rearrangement produces 2,6-diones. The method was successfully utilized for the synthesis of (±)-pleodendione with improved yields versus those of the traditional PDC-TBHP method.