Trifluoromethyl ketones 1 and 2, have been prepared from trisnorsqualene aldehyde 3. These compounds and their corresponding alcohols 4 and 7 have been found to be good inhibitors of the biosynthesis of cholesterol in HepG2 cells. The inhibition is correlated with a decrease of the HMG-CoA reductase activity, probably resulting from the transformation of the fluorinated compounds into their corresponding oxysterols which could act as repressors of that enzyme. (C) 2000 Elsevier Science Ltd. All rights reserved.