Synthetic transformations of natural diterpenes. Synthesis ofalkaloid-likecompounds from lambertianic acid

Abstract

By oxidation of methyl lambertianate with potassium permanganate, the esters of 17-nor-8-keto- and 17-hydroxy-8,12-epoxy-labdadienic acids have been obtained. Reductive amination of the above carbonyl compounds and subsequent intramolecular aminomethylation of 17-nor-8(R)-methylamino- and 17-methylamino-labdadienoates by formaldehyde leads to the formation of novel polycyclic compounds, which are derivatives of furoazocines and furoazonines.