Organic dye-photocatalyzed fluoroalkylation of heteroarene-N-oxide derivatives?

Organic & Biomolecular Chemistry Pub Date: 2018-08-29 DOI: 10.1039/C8OB01653D

Abstract

The 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.

Graphical abstract: Organic dye-photocatalyzed fluoroalkylation of heteroarene-N-oxide derivatives
Recommended Literature