Oxidation of Terpenoid Diols with Chlorine Dioxide: Preparation of Ketols and α-Chlorohydroxyketones of Carane and Pinane Structures

摘要

Vicinal terpenoid diols of carane- and pinane-type structures have been oxidized with chlorine dioxide in pyridine to form the corresponding ketols in the preparative yield of 52-72%, the selectivity of a-hydroxyketones formation being 80-90%. It has been shown that the diols reactivity towards oxidation with ClO2 depends mainly on the stereochemistry of hydroxy groups. The catalysts, VO(acac)2, Mo(CO6), and MoCl5 have practically no effect on the oxidation process. When the reaction has been performed in dimethylformamide, the hydroxyketone chlorination occurred at high conversion.