Two diastereoisomeric(4S)-p-menth-1-ene-8, 9-diols are important intermediates in the synthesis of Ying Zhao Su D. Their preparation were completed through preparation and isolation of the diol derivatives 6a and 6b. The diol mixture 8 obtained from (S)-(-)-limonene by oxidation with Pb(OAC)~4 was treated with phosgene, followed by bromination to give compounds 6a and 6b, which could be separated by flash chromatography in multigram amount, if necessary, further purified by recrystallization. Deprotection of 6a or 6b gave the title compounds. The 8-C configuration was asigned by comparison with corresponding (4R)-series produet.

Key words: SYNTHESIS METHODS, LEMONENE