BUILDING-BLOCKS FOR THE STEREOCONTROLLED SYNTHESIS OF 1,3-DIOLS OF VARIOUS CONFIGURATIONS

A Sharpless epoxidation of the pentadienol 12 afforded the unsaturated epoxyalcohol 11 with 97.7% ee. Silylation of 11 and ozonolysis provid ed the epoxyketone 14. A completely anti-selective reduction of 14 suc ceeded with Zn(BH4)(2). It led to the epoxyalcohol 15 which was conver ted into the acetonide alcohols 21 and 23, building blocks for enantio pure anti-1,3-diols. Alternatively, the same epoxyketone 14 and cp(2)T i(III)Cl / 1,4-cyclohexadiene gave the beta-hydroxyketone 16. This com pound was transformed into the acetonide alcohols 22 and 24, building blocks for enantiopure syn-1,3-diols.