Method for producing 5alpha-pregnane derivative

摘要

The present invention relates to a method of producing a mixture of 5_alpha-pregnane derivatives represented by the formula (II) and the formula (III), which is characterized by reacting a pregnane derivative represented by the formula (I) with a metal selected from alkali metals and alkaline earth metals in the presence of a proton donor and an amine and/or ammonia. According to the present invention, a method capable of producing 5_alpha-pregnane derivatives useful as synthetic intermediates for squalamine, in a high yield from easily available raw materials, can be provided: wherein R¹ is a hydroxyl-protecting group, and R², R¹¹ and R¹² are each independently a hydrogen atom or a hydroxyl-protecting group.