Method for the preparation of 6alpha-fluoro corticosteroids

A method for producing a 6alpha-fluorinated corticosteroid or derivative thereof by reacting a 17-hydroxy-21-ester epoxide of Formula II with a stereoselective fluorinating agent to stereoselectively form a 21-ester-17-hydroxy 6alpha-fluorinated compound of Formula VII R1 can be OC(O)-Rd; R4 can be C(O)-Rd; R3 can be H or Rd. Each Rd may be the same or different and is independently selected from (C1-4)alkyl, aryl and heteroaryl. The dashed line can be a single or a double bond. R4 may be, for example, acetyl; R3 may be, for example, alpha or beta methyl; R4 may be, for example, acetate or propionate. The stereoselective fluorinating agent used in the reaction may be, for example, a fluoropyridinium or fluoroquinuclidium compound, for example, Selectfluor(R).