A method of prepg. fluoromethyl esters of androstane-17_-carboxylic acids of formula I [R1 = OH, ester, carbonate; R2 = H, alkyl; X1, X2 = H, halo; X3 = O, S] is described. The process involves protection of the C11 hydroxyl group and the C17 acid followed by fluorodecarboxylation. Thus, fluticasone propionate and fluticasone furoate were prepd.