PURPOSE: To obtain the titled compound usefuel as an anti-inflammatory agent in high yield, by reacting a reaction product of a specific carboxylate and a fluorine gas with a 11β-hydroxysteroid compound.

CONSTITUTION: A carboxylate (e.g., CH3COONA, etc.) shown by the formula RCOOM (R is lower alkyl; M is alkali metal) is reacted with a fluorine gas usually diluted with an inert gas into ≤20mol%. The prepared reaction mixture is reacted with a 11β-hydroxysteroid compound such as a compound shown by the formula I (R is H, OH, or acyloxy; R1 is acyl, or alkyl; Z is H, OH, or acyloxy; W is H, OH, or CH3; Y is H, or halogen; X is H, halogen, or alkyl), etc., to give the desired compound shown by the formula II, etc. A neutral or weakly acidic solvent (e.g., chlorofluorocarbon compound, etc.) is usually used and the reaction is carried out preferably at -80W0°C.