Abstract
We normally imagine the aromatic diterpenoids to possess the abietane skeleton but several natural products are known with an n-propyl group at C.13 as opposed to the customary iso-propyl residue. From the synthetic point of view, dehydroabietic acid 5a is an ideal starting material for many diterpenes since it boasts a deeply implanted asymmetry at C.10 which resists all but the most energetic reaction conditions. A simple direct method of replacing the C.13 iso-propyl residue of this inexpensive naturally available compound by other substituents could extend its usefulness considerably.