Some aspects of the oxidation of deoxyhumulones to humulones

Abstract

The synthesis and comparative reactivity to oxygen of a series of substituted phloroglucinols is used to define the structural patterns associated with the reactivity of deoxyhumulones to oxygen under very mild conditions. The relative reactivity of phloroglucinols bearing unsaturated alkyl side chains as compared with those bearing alkyl groups is investigated by intermolecular and intramolecular competitive experiments with model compounds. The acyldialkyl- and trialkyl-phloroglucinols react readily with oxygen, and we suggest that oxidation of the aromatic ring precedes oxidation of side-chain double bonds in the reaction of the deoxyhumulones with air or oxygen.