Products from the solvolysis of unsaturated 3-steroidal toluene-p-sulphonates

Abstract

The solvolysis products of the reactions of 3α- and 3β-p-tosylates of 5α-cholestan-3-ols, 5α-cholest-6-en-3-ols, and 5α-cholest-7-en-3-ols in acetic acid and a 50/50 mixture of acetic acid–formic acid have been determined. Equilibrium constants for the corresponding epimeric pairs of 3-sterols in potassium pentyl oxide–t-pentyl alcohol have been measured. Substantially more olefin was produced from the solvolysis of the axial derivatives and for all substrates more olefin was obtained in AcOH–HCOOH compared to AcOH. The different elimination/subsitution and inversion/retention ratios for the p-tosylate solvolyses have been interpreted in terms of conformational transmission.