Functionalization at C12 of labdanolic diterpenesnext term synthesis of α- and β-levantenolide

Abstract

Several Cl2 oxygenated labdanolic diterpenes have been isolated in the last few years, principally from species of Nicotiana 1,2. As up to now, no efficient synthesis of these products have been reported and also considering that biogenetic routes to these compounds have been hypothesized from abienol through 12-keto intermediates, we have developed a method of preparing some Cl2 oxygenated labdanolic diterpenes starting from the readily available labdanolic acid 1a. An application of this method led us to a simple synthesis of α- and β-levantenolide.