Process for the production of estetrol intermediates

Abstract

The present invention relates to a process for the preparation of a compound of formula (I) comprising the steps of a) reacting a compound of formula (II) with a silylating or an acylating agent to produce compound of formula (III), wherein Pis a protecting group selected from R—Si—RRor RCO—, Ris a group selected from Calkyl or Ccycloalkyl, each group being optionally substituted by one or more substituents independently selected from fluoro or Calkyl; R, Rand Rare each independently a group selected from Calkyl or phenyl, each group being optionally substituted by one or more substituents independently selected from fluoro or Calkyl; b) halogenation or sulfinylation of the compound of formula (III) to produce a compound of formula (IV); wherein X is halo, or —O—SO—R, and Ris a group selected from Caryl or heteroaryl, each group being optionally substituted by one or more substituents independently selected from chloro or Calkyl; c) dehalogenation or desulfinylation of the compound of formula (IV) to produce compound of formula (V); and d) reacting the compound of formula (V) with a reducing agent to produce compound of formula (I).