Conversion of a Cyclic α,β-Unsaturated Ketone into a Tertiary Dienyl Hydroperoxide: Application to the First Hemisynthesis of 15-Hydroperoxyabietic Acid

Abstract

The first hemisynthesis of 15-hydroxyperoxyabietic acid, a major contact allergen among the oxidation products of colophony, is reported. The key step includes a new approach to easily obtain a dienyl tertiary hydroperoxide from a cyclic α,β-unsaturated ketone. The procedure is based on the formation of a bromodiene using a Vilsmeier's reagent, followed by a halogen/metal exchange and alkylation with acetone, to afford the dienyl alcohol precursor of the hydroperoxide.