Stéréochimie—LIV

The topological isomerism between octalinones in which the enone group has two distinct locations does not lead to any difference on the stereochemistry of the hydrocyanation of these substrates; the cyano group is axial in the kinetically controlled products. On the contrary, the stereoselectivity is strikingly reversed when the enone group is substituted by a methyl β to the carbonyl, leading to the introduction of the cyano group in an equatorial configuration in the kinetically controlled products.