Ligand-assisted manganese-enabled direct C–H difluoromethylation of arenes†

Abstract

The incorporation of a difluoromethyl group within an aromatic ring is highly desirable. However, studies on direct C–H difluoromethylation reactions of arenes have been sparsely reported in the literature. Therefore, in this work, a light-induced Mn-enabled DavePhos-promoted direct C–H difluoromethylation reaction of general arenes has been explored in detail using ArSO₂CF₂Br with variable characteristics as the coupling partner under mild conditions. Various arenes and bioactive molecules were all well tolerated, producing the resultant products in moderate to high yields. Preliminary mechanistic studies suggested that Mn₂(CO)₁₀ could not only mediate the halogen-atom transfer process (XAT) to provide active ArSO₂CF₂˙ radicals but also coordinate with the arenes through π-complexation to activate the aromatic ring. This facilitated the reaction between the aromatic ring and the ArSO₂CF₂˙ radical.