Isomerization of Caryophyllene Oxide Catalyzed by Solid Acids and Bases

Abstract

Abstract The reaction of caryophyllene oxide over eleven catalysts of solid acids and bases gave 4,5-dihydrocaryophyllen-5-one (III), (1R, 5S, 8R, 9R)-4,4,8-trimethyltricyclo[6.3.1.01,5]dodeca-2-en-9-o1 (IV), (2S, 5R, 9R)-caryophylla-1(12),8(15)-dien-9-ol (V), (2S, 5R, 9R)-caryophylla-1(12),7-dien-9-ol (VI), and (2S, 5R, 9S)-caryophylla-1(12)-7-dien-9-ol (VII). A large amount of III was formed together with IV over FeSO4 and Zr(SO4)2. Allylic alcohols (V, VI, and VII) were preferentially given by Al2O3–II and TiO2–ZrO2 in >74% selectivity: 96% on TiO2–ZrO2. Other catalysts formed three to five species of the products uniformly.