1: tetrakis(triphenylphosphine) palladium(0); trimethylsilylazide / 1,2-dichloro-ethane / 1 h / Inert atmosphere; Reflux 2: sulfur; 2,3-dicyano-5,6-dichloro-p-benzoquinone / 1,2-dichloro-ethane / 1 h / Inert atmosphere; Reflux View Scheme