Addition-elimination reactions of fluoroxytrifluoromethane with activated aromatics

Modified taxols. 3. Preparation and acylation of baccatin III

“…His results showed the dual mechanistic nature of CH3COOF: transfer of fluorine ions and addition.3*1 We have previously shown that CF3OF adds to the aromatic nucleus of pyrenol.6 78The addition of CsS04F to the aromatic nucleus is apparently a much less desirable process than is the addition of CHgCOOF or CF3OF. Reaction of 17/3-estradiol (4) and CsS04F/BF3 provided a clean and simple preparation of two fluorinated isomers: 2-fluoro-17d-estradiol (5) and 4-fluoro-17/3-estradiol (6). Both fluorinated isomers were useful in the study of cancer therapy with estrogens.7,8 The present synthesis is especially attractive because the products are produced in…”

Selective Fluorinations by Reagents Containing the OF Group

“…In 1986 Purrington wrote a review on F 2 and various hypofluorites and their role in organic chemistry, 157 and Rozen published several monographs including an account of his research with fluorine and various hypofluorites. 158 Mann covered selected literature dealing with hypofluorites, 159 while Firnau concentrated on the synthesis of 18 F-containing compounds and their synthesis with AcOF. 160 Yagupolskii reviewed the synthesis of optically active aromatic amino acids mainly phenyl alanine and tyrosine where the aromatic fluorine was introduced with acetyl and other hypofluorites.…”

“…Similar results were obtained by Mulholland who eliminated the solvent and used a column of dry, solid CF 3 COONa through which he passed F 2 , thus obtaining CF 3 CF 2 OF, CF 3 -CF(OF) 2 , CF 3 OF, and CF 2 (OF) 2 . These experiments were repeated with 18 F-19 F fluorine gas, having positron emitting tomography (PET) experiments in mind. 58 If, however, the salt is hydrated, the fluoride ion in the NaF which is first formed loses its nucleophilic power and mainly trifluoroacetyl hypofluorite, CF 3 COOF, results (Scheme 33).…”

“…One of the main forces in the development of acetyl hypofluorite chemistry was the rapidness of its preparation which made it suitable for work with the positron-emitting isotope 18 F which has a half-life of 110 min. Although the specific activity was never very high, its easy preparation from neon (Scheme 43), and its fast reactions with double bonds made this reagent very attractive for positron-emitting tomography (PET) studies.…”

“…Aromatic fluorination was also reported by Belanger, who reacted CF 3 OF with 1,3-dimethoxybenzene (Scheme 4), 15 and by Chambers, who reacted it with metal aryl, especially mercury, derivatives to obtain monofluoro derivatives in good yields (Scheme 5). 16 Patrick found that even at -78 °C, the main side reaction of activated aromatic molecules, 17 as well as of polycyclic aromatics such as coronene, 18 was the addition of CF 3 OF across the most electron-rich π region of the ring to form unsaturated fluoro and difluoro ketones (Scheme 6). If large excess of fluoroxytrifluoromethane was used the remaining double bonds also reacted to give a complex mixture which was difficult to separate.…”