Direct C−H Arylation and Alkenylation of 1-Substituted Tetrazoles: Phosphine As Stabilizing Factor

Direct arylation and alkenylation of 1-substituted tetrazoles was achieved via Pd catalysis in the presence of CuI and Cs<sub>2</sub>CO<sub>3</sub>. Unlike the related reactions of imidazoles and purines, phosphine ligand was necessary to prevent the intermediate tetrazolyl-Pd<sup>II</sup> species from fragmentation into the corresponding cyanamide. Various 1,5-disubstituted tetrazoles were prepared with good to excellent isolated yields.