Abstract: We reported a facile synthesis of (-)-isochrysanthenone(2) from (-)-α-pinene in a high yield. When(-)-α-pinene reacted with O₂ in the presence of Co[4-Me(C₅H₄N)₂]Br₂ used as a catalyst, the crude product of (-)-verbenone(1) was formed, and the crude product 1 was directly irradiated with ultraviolet light and converted into the (-)-isochrysanthenone(2). The structure of compound 2 was converted to a cyclic ester(4) by Baeyer-Villiger oxidation, the compound 4 was hydrolyzed to form a crystal 2,2,4-trimethyl-5-oxy-3-cyclohexenyl carboxylic acid 5. Compound 5 was confirmed by IR, ¹H NMR and X-ray crystal analysis. In summary, we found that under the condition of photochemical rearrangement of (-)-verbenone and (+)-verbenone, different compounds were obtained, they are not enantiomers.

Key words: Pinene, (-)-Verbenone, (-)-Isochrysanthenone