Oxidation of several triterpenic diene and triene systems. Oxidative cleavage to obtain chiral intermediates for drimane and phenanthrene semi-synthesis

An exhaustive oxidation study has been made with ozone, MCPBA and/or NaIO4/RuCl3 of several triterpenic diene and triene compounds from oleanolic and maslinic acids obtained from olive-oil pressing. Through several oxidative cleavages of the opened C-ring of these oleantrienes, different significant decalin-type chiral synthons were achieved. These sesquiterpene and nor-sesquiterpene products are of great interest because by means of several simple reactions they could lead to drimane, phenanthrene and tricyclic triterpene compounds.