Abstract: Astereoselective synthesis of (3 S,5S,6S )-3,7-dimethyl-5,6-dihydroxy-7-en-octanal, a key intermediate, for the synthesis of the HIVinhibitory didemnaketals analogue, was performed via a series of reactions from the natural(+)-pulegone. In this approach, an interesting and valuable diastereo recognizable reaction between tertiary hydroxyepoxides and PCCwas found. Therefore, the mixture of compounds 8 and 9 was treated with PCCto recover 8 in 93% yield and de 98% purity.

Key words: Spiroketal, R-(+)-Pulegone, Diastereo-recognizable oxidation reaction, 3,7-Dimethyl-5,6-dihydroxy-7-en-octanal intermediate