Applications of high-potential quinones. Part 11. Remote substituent effects in the benzylic oxidation of aromatic steroids

Abstract

Rates of dehydrogenation of ring A aromatic steroids by dichlorodicyanobenzoquinone are markedly influenced by substituents in ring D. The presence of sp²-hybridization at C-17 inhibits styrene formation, and a 16α-chloro-group further decreases the rate of oxidation at C-9. Relief of the strain energy in the C/D-trans-ring junction does not contribute significantly to the more rapid dehydrogenation of ring B aromatic steroids, judging by the relative rates of oxidation of de-A-oestratrienes and deoxyoestrogens.