Stereoselective Addition of Pyridyl Lithium to 22‐Aldehyde Steroid. Synthesis of 22‐Piperidin‐yl‐pregnan‐3β, 22(S)‐diol

Abstract

A short synthesis of two new 22‐piperidin‐yl‐pregnan‐5‐en‐3β,22S‐ols from 23,24‐bisnor‐5‐cholenic acid‐3β‐ol is described. The addition of pyridyl lithium to 3β‐tetrahydropyranyloxy‐23‐bisnorchol‐5‐en‐22‐al 5 affords the 22α, 22S hydroxy configuration with high diastereoselectivity as measured by NMR (84–90% de).

Keywords:

• Azasterols
• Pyridyl lithium
• 22‐Aldehyde steroid

Acknowledgments

This work was supported by the Instituto Venezolano de Investigaciones Cientificas (IVIC‐Venezuela), and the Fondo Nacional de Ciencia, Technología e Innovación (Proyecto S1‐2001000664).

We thank Dr. Teresa Lehmann for her help in the redaction of the manuscript, and Sara Pékerar for technical assistance.