1.1: triethylamine / tetrahydrofuran / 1 h / 0 - 20 °C 2.1: polyphosphoric acid / 1 h / 150 °C 3.1: dimethylsulfide borane complex / tetrahydrofuran / 19 h / 0 °C / |Reflux 3.2: 18 h / |Reflux View Scheme

copper(l) iodide; triethylamine in N,N-dimethyl-formamide T=20°C; 24 h;