Composición para la preparación de 17-vinil-triflatos como intermedios

摘要

A compound of formula (I):
or a pharmaceutically-acceptable salt thereof, may be made by a process including a triflating step by which a ketone of formula (II) is converted into a triflate of formula (III):
in the presence of a base comprising a tertiary or heterocyclic amine such that the pK a of the conjugate acid at 25 °C is within the range 5.21 to 12.