PROCESS FOR PRODUCING 7alpha-PROPYLSTEROIDS

A process is used for producing 7alpha-propylsteroids having general formula (I), wherein R1 is a beta-hydroxy group and R2 is hydrogen or a alpha linked -CH2-CH2COOR5 residue, R1 and R2 form together the residue (A), R3 and R4 are hydrogen, R3 and R4 form together a methyl residue, which can be alpha or beta linked, and R5 is hydrogen, sodium or potassium. The process is characterized by the fact that 4,6 unsaturated steroid ketones having general formula (II), wherein R1-R4 have the above-mentioned meaning, are converted with an alkyltrialkyl compound having the general formula (III): CH2=CH-CH2-X(alkyl)3, wherein X is Si or Sn and alkyl is C1-4-alkyl, in the presence of a Lewis acid and finally the 7alpha-propenyl side chain thus obtained is selectively hydrated.