A 1,3 ‐strain mediated epimerization of 2e,3e,5e,6e‐tetraarylpiperidin‐4‐one oximes

A series of tri‐ and tetraarylpiperidin‐4‐one oximes were synthesized from 2e,3e,6e‐tri‐ and 2e,3e,5e,6e‐tetraarylpiperidin‐4‐ones, respectively. In the case of the latter compounds, oximation is accompanied by epimerization at C‐5 to avoid the A 1,3 ‐strain between the oxime OH group and the 5e‐aryl ring of the initially formed oxime resulting in 2e,3e,5a,6e‐tetraarylpiperidin‐4‐one oximes. 1 H, 13 C and 2D NMR spectroscopic data were employed to characterize and investigate the stereochemistry of these compounds. Copyright © 2004 John Wiley & Sons, Ltd.