Catalytic formation of C(sp3)–F bonds via decarboxylative fluorination with mechanochemically-prepared Ag2O/TiO2 heterogeneous catalysts

Abstract

Mechanochemically-prepared, Ag₂O-containing solid materials, are shown to be efficient heterogeneous catalysts for the synthesis of C(sp³)–F bonds via decarboxylative fluorination. Five catalytic cycles without loss of intrinsic activity could be performed with the optimal catalyst, composed of 1 wt% Ag₂O supported on TiO₂ (P25), despite the challenging conditions. The catalyst is easily prepared from the corresponding oxides in 20 minutes by simple mechanical mixing methods. In addition to ease of separation and re-use, the turnover numbers obtained over the solid catalyst are over one order of magnitude higher than those obtained with the state-of-the-art homogeneous catalyst, AgNO₃, under otherwise identical conditions. To the best of our knowledge, this represents the first true heterogeneous catalyst for the selective formation of C(sp³)–F bonds with electrophilic fluorine donors, representing a major breakthrough in the field of catalytic fluorination.