Abstract
Reaction of 12-acetyl ester (5) with aluminum chloride gave predominant trans-isomer (6) in company with the cis (7). trans-Isomer had not been observed as major product in the reactions of methyl dehydroabietate having electron-donating group at aromatic ring as described previously. In the other cases of reactions of methyl dehydroabietate derivatives having electron-withdrawing group, 7-oxo ester (20) did not react even under the drastic condition. But 7-oxo ester having a hydroxyl or a methoxyl group at 12-or 14-position was deisopropylated to give only the respective trans deisopropyl isomer.
