Site-Specific Dehydrogenative\nHydroxyfluoroalkylation\nof Indoles with Hexafluoroisopropanol

An\nefficient and convenient method for the synthesis of C3-hydroxytrifluoroalkylated\nindoles and pyrroles was described in this paper. The copper-catalyst-free\nsite-specific cross-dehydrogenative coupling reaction of various indoles\nand pyrroles with hexafluoroisopropanol proceeded smoothly by using\nMnO<sub>2</sub> as oxidant to furnish a hydroxytrifluoroalkylated\nelectron-rich <i>N</i>-heterocycle in satisfactory to excellent\nyields. Various groups, including the synthetically useful functional\ngroups Cl, NO<sub>2</sub>, and CN, were tolerated well. The mechanistic\nstudy revealed that a radical pathway accommodated the formation of\na hexafluoroacetone intermediate.