Preparation of fluoro compounds

Process for the preparation of a fiuoro-compound by reaction of a reactive oxy-acid ester or a reactive cyclic ether other than an anhydrouridine with hydrogen fluoride wherein the reaction is carried out under anhydrous conditions in the presence of an organometallic compound of formula:

• MY.sub.m Z.sub.n (I)
• where M is a 4-, 6-, or 8-coordinated metal wherein said metal is iron, Y is a monodentate ligand, Z is a bidentate ligand or a cyclopentadienyl ligand, and m and n are each zero or positive integers such that (m +2 n)=4, 6 or 8.