Assembling of new C-C and C-heteroatom bonds in natural products of potential biological activity can provide opportunities for broadening of molecular diversity, leading to new chemical space, in addition to trivial functional group transformations. We have initiated a program for modification of available terpenic scaffolds by free radical [1] and cationic [2, 3] processes and examples reported in this communication relate to labdanic 1, ent-kauranic 2 and isocopalic 3 diterpenoids. They represent important groups of natural products with relevant properties and applications.Manoyl oxides have been used to several radical reactions, such as hydroazidation, carboazidation, hydroalkynation and carboiodination. At the carboiodination reactions iodine migration was observed at the distal methyl from cycle A of substrate, involving 3 successive 1,5-HAT [4]. As with manoyl oxides, ent-kauranic derivatives were modified by radical reactions. Were synthesized five new azides, which were converted into amines, triazoles, amides, lactams and guanidine in very good yields. Many functional groups, for example: -N3, -SO2Ph, -CF3(CF2)n, CF3 and etc., were introduced in structure of kaurane derivatives Carboazidation of isocopalic ditepenoids with ethyl iodoacetate and phenylsulfonyl azide under DTBHN initiation conditions resulted in the formation of the azides in good yields. In that case, it was demonstrated that we can get good results not only with natural compounds having terminal double bond, but also with non-terminal such as methyl ent-isocopalate 3. In the result of the performed investigations, 85 new functionalized compounds have been synthesized. Preliminary biological activity studies revealed relevant cytotoxicity of some selected derivatives against several cancer cell lines.