| Abstract
| - The preparation of the 10-trifluoromethyl hydroartemisinin, followed by dehydration, afforded thetrifluoromethyl analogue 2 of anhydrodihydroartemisinin 1. The reactivity of these two glycals ofartemisinin were compared in epoxidation and halogenation reactions. Iodination of glycal 1 inwater and the further rearrangement of the produced iodo hemiacetal provided the new D-ring-contracted aldehyde 8α, where the methyl at C-9 is β. Epoxidation of 10-trifluoromethylanhydrodihydroartemisinin 2 stereoselectively provided the β-epoxy ether 11 in high yield. Whentreated with hexafluoro-2-propanol or trifluoroethanol, 11 readily underwent a rearrangementyielding to the D-ring-contracted trifluoromethyl ketone 9α with retention of configuration at C-9.
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