Potential Ambergris Odorants From Abietic Acid

Abstract

In contrast to literature reports the rearrangement of abietic acid (1) catalysed by 96% sulfuric acid gives a mixture (3 : 1) of two dienoic acids (19) and (27) whose structures have been established by spectral means. Compounds containing the diene system are unstable, severely limiting their use in synthesis. However, removal of the diene functionality affords stable compounds which, despite difficulties in stereochemical control, are suitable for further modification. The synthesis of compounds containing a five- membered C-ring common to a class of potential amber odorants is reported.