A stereoselective synthesis of (3S,5S,6S)-3,7-dimethyl-5,6-dihydroxy-7-en-o
ctanal, a key intermediate, for the synthesis of the HIV-inhibitory didemna
ketals analogue, was performed via a series of reactions from the natural()-pulegone. In this approach, an interesting and valuable diastereo-recogni
zable reaction between tertiary hydroxyepoxides and PCC was found. Therefor
e, the mixture of compounds 8 and 9 was treated with PCC to recover 8 in 93
% yield and de 98% purity.