The scientific interest in diterpenic tetracyclic ent-kaur-16-en-19-oic acid (1) is explained by the fact that this compound possesses a broad spectrum of biological activities [1-3]. It was isolated from different vegetal sources, especially from sunflower Helianthus sp. [4]. Polyfunctionalized tetracyclic ent-kauranic terpenoids are also of a great interest, as a result of their pronounced biological activity. For the functionalization of ent-kaur-16-en-19-oic acid (1) the catalytic version of Prevost - Woodward reaction was used. We report herein the results of the transformation of ent-kaur-16-en-19-oic acid (1) catalyzed by LiBr and mediated by NaIO4, using the method described in the literature [5]. As a result, a mixture of diterpenic compounds was obtained, which was purified by column chromatography, resulting in the isolation of the functionalized ent-kauranic diterpenoids (2) – (6). Their structures were elucidated by NMR and IR spectroscopies. It should be mentioned, that diterpenoids (2), (3) and (5) containing a bromine atom at C-17 can potentially be endowed with interesting biological properties.figureFigure 1. Functionalization of ent-kaur-16-en-19-oic acid. As a result of Prevost–Woodward transformation of ent-kaur-16-en-19-oic acid (1), new derivatives of ent-kaurenic acid, functionalized at C-15, C-16 and C-17 carbon atoms, have been obtained.