Catalytic transformations of (+)-aromadendrene: Functionalization and isomerization reactions in the presence of the heteropoly acid catalyst H3PW12O40

Abstract

Transformations of the naturally occurring compound (+)-aromadendrene (1) were performed in the presence of the heteropoly acid catalyst H3PW12O40, a technologically efficient homogeneous catalyst, which, in principle, can be recovered from polar solutions by precipitation using a nonpolar solvent. In solutions of n-butanol and ethanol, there was the formation of (+)-ledene resulting from isomerization of the double bond in the carbon chain of the substrate and the ether produced by nucleophilic addition of the alcohol molecule to the exocyclic double bond of 1. In ethanol solution, in addition to formation of (+)-ledene and the ether product derived from ethanol, there was also the formation of a product formed by the addition of a water molecule to the (+)-aromadendrene double bond. The products, alone or mixed, presented pharmacological properties and have the potential for commercial application. The simple catalytic process developed in this work is a technologically attractive route, which employs a renewable substrate for the production of compounds with potential uses in the fine chemical industry.