Skeletal Clipping of 4-Hydroxycoumarin toward Functionalized 2-Aminofluorenyl-2′-Hydroxyphenone Derivatives

Abstract o-Amino- and o-hydroxyl-substituted benzophenones are valuable scaffolds in organic synthesis, catalysis, and materials science. Herein, we describe a highly efficient DABCO/KF cooperative-mediated skeletal clipping strategy that converts readily available 4-hydroxycoumarin and indene-based dienes into functionalized 2-aminofluorenyl-2′-hydroxyphenones in a single operation. Furthermore, the synthetic utility of the resulting products is illustrated by further derivatization and preliminary applications as ligands in Heck coupling and as photocatalysts in alcohol oxidation. A plausible reaction mechanism was proposed based on control experiments.