Selective oxidation of limonene (1) with benzoquinone in the solutions of various alcohols (methanol, ethanol and 2-propanol) containing catalytic amounts of palladium(II) complexes and p-toluenesulfonic acid has been carried out. Two isomeric allylic ethers have been characterized as major products in each alcohol, showing that they arise from either exo- or endocyclic eta(3)-alkyl intermediates formed by the reaction of palladium catalysts with the endocyclic C=C bond of limonene. A good control of regioselectivity was achieved through the appropriate choice of the ligand on palladium and reaction conditions. Allylic ethers 2a-c with two exocyclic double bonds are main reaction products in chloride-free catalytic systems, while carveol derivatives 3a-c are formed when palladium chloride is used as the catalyst. p-Toluenesulfonic acid exerts a great accelerative and catalyst stabilizing effect in these reactions. Monoterpenic ethers 2a-c and 3a-c have mild scents of flower or fruit and can be useful as components of synthetic fragrances. These compounds were obtained in 80-97% chemoselectivity each at a limonene conversion of 95-98% under appropriate conditions.(c) 2006 Elsevier B.V All rights reserved.