Method for the preparation of 6alpha-fluoro corticosteroids

A method for producing a 6 -fluorinated corticosteroid or derivative thereof by reacting a 17-hydroxy-21-ester epoxide of Formula II 1 with a stereoselective fluorinating agent to stereoselectively form a 21-ester-17-hydroxy 6 -fluorinated compound of Formula VII 2 R 1 can be OC(O)-R d ; R 4 can be C(O)-R d ; R 3 can be H or R d . Each R d may be the same or different and is independently selected from (C 1-4 )alkyl, aryl and heteroaryl. The dashed line can be a single or a double bond. R 4 may be, for example, acetyl; R 3 may be, for example, alpha or beta methyl; R 4 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®.