Catalytic oxidation of α-pinene by transition metal using t-butyl hydroperoxide and hydrogen peroxide

The allylic oxidation of alpha-pinene 1 was investigated using various catalytic systems. By a proper choice of the latter, the reaction can be directed toward the selective synthesis of verbenol 2 or verbenone 3. High yield into verbenone was achieved under mild conditions with copper salts as catalysts and t-butyl hydroperoxide (TBHP) as oxidant. On the other hand, when Pd(acac)(2) was used with hydrogen peroxide, verbenol was obtained as the main product. (C) 2003 Elsevier Science B.V. All rights reserved.