Quadruple switchable catalysis: sp3 C–H arylation, aminomethylation, sp2 C–H arylation, and deiodination

A quadruple switchable selective catalytic system was developed, enabling sp3 C–H arylation, aminomethylation, sp2 C–H arylation, and deiodination using aryl halides and formamides. The selectivity of this protocol was governed by the amine derivatives, wherein ammonium formate promoted sp3 C–H arylation, triethanolamine favored aminomethylation, and tripropanolamine facilitated sp2 C–H arylation. Additionally, temperature was found to play a crucial role, with aminomethylation occurring at 150 °C and deiodination at 110 °C. All reactions were performed using a reusable silicon nanowire array-supported Pd catalyst with an ultralow Pd loading of 65 mol ppm. The use of microwave irradiation was essential for promoting the catalytic reaction, with the magnetic field component proving more effective than the electric field. Finally, plausible catalytic pathways were elucidated through mechanistic experiments and density functional theory calculations.