Enantiodivergent total synthesis of trioxilins B3 using Sharpless asymmetric olefin dihydroxylation

The unknown 11,12-threo-stereoisomers of B-type trioxilins, (10R, 11R, 12S)-TrXB3, its (10S)-epimer and their enantiomers were synthesized (as methyl esters) from a common racemic precursor, viz., methyl rac-10-hydroxyeicos-11(E)-ene-5,8,14-triynoate, by Sharpless enantiodirected dihydroxylation of the double bond as the key step.