2,2'-azo-bisisobutyronitrile; tri-n-butyl-tin hydride in benzene T=80°C; 2 h;

zinc copper in ethanol; water Ambient temperatureunder sonication;;

1: 80 percent / tetramethylguanidine / acetonitrile / 24 h / Ambient temperature 2: 82 percent / Bu3SnH, azobis(isobutyronitrile) (AIBN) / benzene / 2 h / 80 °C View Scheme