Organic Dye-Photocatalyzed Perfluoroalkylation of Heteroarene-N-oxide Derivatives

BEATRIZ LANTAÑO; BARATA VALLEJO, S; AL POSTIGO

ORGANIC & BIOMOLECULAR CHEMISTRY

ROYAL SOC CHEMISTRY

Lugar: CAMBRIDGE; Año: 2018 vol. 16 p. 6718 - 6727

1477-0520

DOI: 10.1039/c8ob01653dThe first direct CHet-H perfluoroalkylation reaction of heteroaromatic-N-oxides has been achieved through a visible light-photocatalyzed reaction in the presence of commercially available perfluoroalkyl iodides RF-I and base in DMF as solvent and Rose bengal as organic photocatalyst. The reactions proceed in the absence of transition metals and can be scaled up. Through an acid-catalyzed transformation of the perfluoroalkylated-N-oxides thus obtained, the first direct syntheses of 2-(perfluoroalkyl)benzo[f][1,3]oxazepines are achieved. De-oxygenation of the resulting perfluoroalkylated heteroaromatic-N-oxides leads to high yielding and regioselective radical perfluoroalkylation protocols of heteroaromatic compounds. To the best of our knowledge, this is the first report on a direct method for perfluoroalkylation of pyridine-, quinoline-, and diazine-N-oxide derivatives