Copper oxidation chemistry using a 19-iminopyridine-bearing steroidal ligand: (i) C5-C6 olefin difunctionalization and (ii) C1β-hydroxylation/C19-peroxidation.

The Schönecker oxidation involves the 12beta-hydroxylation of 17-imino pyridine DHEA derivatives using copper and either molecular oxygen or hydrogen peroxide as the oxidant. In this study, a 19-imino pyridine DHEA derivative was synthesized and was treated with copper nitrate and hydrogen peroxide. Our results showed the difunctionalization of an olefin for delta-5 steroid substrates to yield a 5beta-hydroxylated 6alpha-nitrate ester product. In contrast, for 19-imino pyridine precursors with a 5alpha-androstane steroid backbone: a 1beta-hydroxylation and 19-peroxidation occurred to yield a 1beta-hydroxylated 19-imidoperoxoic acid product. In conclusion, new Schönecker oxidation chemistry was discovered (C5-C6 olefin difunctionalization and C1beta-hydroxylation/C19-peroxidation) when a 19-imino pyridine DHEA derivative was used as the substrate.