Palladium Catalyzed Oxidation Of Renewable Terpenes With Molecular Oxygen: Oxidation Of Alpha-Bisabolol Under Chloride-Free Nonacidic Conditions

A novel selective palladium catalyzed oxidation of alpha-bisabolol by molecular oxygen under chloride-free nonacidic conditions has been developed. alpha-Bisabolol is a sesquiterpenic alcohol available from essential oils of various plants. The reaction proceeds in aqueous methanol solutions over the Pd(OAc)(2)/Cu(OAc)(2) catalytic system and gives exclusively the products resulting from the interaction of palladium with a sterically encumbered internal acyclic double bond. No concomitant oxidation of the second double bond, the endocyclic one, occurs. Novel poly-functionalized sesquiterpenoid compounds obtained at the oxidation of alpha-bisabolol are potentially interesting for cosmetic, fragrance and pharmaceutical applications.