Methods of Fluorination in Organic Chemistry

Since the days of the “Manhattan Project” our knowledge of the chemistry of fluorine-con-taining compounds has increased tremendously. At first only considered out of curiosity, this area of research bordering between inorganic and organic chemistry has developed from modest beginnings to such a complexity of interesting ramifications that it would be very difficult to review all aspects in detail. The motivating force behind the developments in this field were, above all, the unusual properties the numerous compounds acquire on introduction of fluorine substituents. The spectrum of unusual modes of behavior extend from extreme stabilization in fluorine-containing polymers and blood-substitutes to drastic increases in reactivity in pharmacologically and phytomedicinally active substances and in dyes. Moreover, one physical peculiarity of the fluorine atom, its magnetic moment, opens a new route to the decyphering of metabolic processes.—Parallel to the ever increasing number of fluorinated compounds there has been a concomitant increase in the variety of methods of synthesis and reagents, which is frequently difficult to overview in entirety, even for the specialists. Older, simple methods such as halogen metathesis with metal fluorides and electrofluorination are being refined as far as higher selectivity is concerned, and completely new, very reactive substances such as hypofluorites and noble-gas fluorides enable fascinating reactions on complex substrates, e. g. steroids and nucleobases. The present review is an attempted documentation and classification of the methods as well as a critical appraisal, not least from the standpoint of efficiency and economic aspects.