Asymmetric synthesis of antimitotic combretadioxolane with potent antitumor activity against multi-drug resistant cells.

Abstract The ( S , S )-enantiomer of combretadioxolane ( 3 ), designed as a chirally preorganized derivative of combretastatin A-4, exhibited quite strong tubulin polymerization-inhibitory activity (IC 50 : 4–6 μM). (S,S)- 3 is 20 times more potent than vincristine as an in vitro growth inhibitor (in terms of GI 50 ) of the multi-drug-resistant (MDR) cell line PC-12, which produces P-glycoprotein.