Oxidation of unsaturated steroid ketones with hydrogen peroxide catalyzed by Fe(bpmen)(OTf)2. New methodology to access biologically active steroids by chemo-, and stereoselective processes

In this paper we describe a new environmentally friendly method to promote the oxidation of steroids. The chemo- and stereoselective aspects of the oxidation of conjugated enones, dienones, further unsaturated enones, estrone, and cholestane acetates were under study.The great facial stereoselectivity of the method has been shown on substrates 12, 14, and 18 improving some of the updated reported procedures in the literature. Reaction with substrate 16 displays the competition between the C4-C5 and the C9-C11 double bonds. The steric hindrance around C ring activates the C-H hydroxylation at the allylic position on C-12 by formation of the allylic alcohol 17c.The C-H activation at C-5 was proven to succeed on the oxidation reaction of androstane 26 by formation of the tertiary alcohol 27.