Bierman and Muserlian
Preparation of 16.alpha.-methyl steroids
 A process for the preparation of a compound of the formula ##STR1## in which rings A and B are a remainder: ##STR2## in which the 3-ketone function is optionally protected in the form of a ketal, thioketal, hemithioketal or enol ether, or a remainder: ##STR3## wherein R is methyl or --CH.sub.2 --OR', R' is hydrogen or ether remainder or ester remainder, R.sub.1 and R.sub.2 together form a second bond, or R.sub.1 and R.sub.2 form together an epoxide in beta position, or R.sub.1 is hydrogen, ketone or .alpha.- or .beta.- hydroxy, free or protected in the form of an ether or ester and R.sub.2 is hydrogen, or R.sub.1 is hydrogen and R.sub.2 is .alpha.-hydroxy function, or R.sub.1 is .beta.-hydroxy, free or protected in the form of an ether or ester and R.sub.2 is .alpha.-fluorine or bromine and R.sub.3 is hydrogen or .alpha. or .beta. fluorine or methyl comprising reacting a compound of the formula ##STR4## in which A, B, R, R.sub.1, R.sub.2 and R.sub.3 have the above meaning with a methylation agent in the presence of a copper-based catalyst to form the 16 .alpha.-methylated enolate, hydrolyzing the latter to obtain the corresponding enol and reacting the latter with an oxidizing agent to obtain the compound of formula I. 
Roussel Uclaf
C C
C07J C07J
inventional inventional
Patrick Michel
Roussel Vivat