Regioselective dehydrogenation of 3-keto-steroids to form conjugated enones using o-iodoxybenzoic acid and trifluoroacetic acid catalysis
摘要:
Mild and regioselective conversion of 3-keto-5 alpha- and 3-keto-5 beta-steroids (trans A/B- and cis A/B-ring juncture, respectively) to the corresponding enones (Delta(1)- and Delta(4)-3-ketones) by treatment with oiodoxybenzoic acid (IBX) catalyzed by trifluoroacetic acid (TFA) in DMSO, is described. The IBX-mediated reaction involved dehydrogenation of the alpha- and beta-hydrogen atoms of the 3-ketones to give the enones regioselectively in good isolated yields without concomitant formation of related dienones and trienones. (C) 2013 Elsevier Ireland Ltd. All rights reserved.