Abstract 12-Methoxypodocarpa-8, 11, 13-trien-19-oic acid (1), its acid chloride (3), and its methyl ester (4) undergo a decarbonylation reaction on treatment with phosphoryl chloride. The products have been identified as the octahydrophenanthrene (14), the tetrahydrophenanthrenes (11) and (12), and the phenanthrene (9). A minor product has been tentatively identified as the dimer (16). Decarbonylation of abieta-8, 11, 13-trien-18- ...
