Dihydroxylation of vinyl sulfones: stereoselective synthesis of (+)- and (-)-febrifugine and halofuginone.

The asymmetric dihydroxylation of amino-functionalized vinyl sulfone 19 has been used for the 3-step preparation of 3-hydroxylpiperidine 24 in 86% enantiomeric excess. This enantiomerically enriched building block was used then to synthesize the naturally occurring antimalarial alkaloid febrifugine 1 and its antiangiogenic analogue, halofuginone 3.