1: N,N-dimethyl-formamide; phosgene / dichloromethane / 5 h / 20 °C / |Inert atmosphere 2: potassium tri-sec-butyl-borohydride / tetrahydrofuran / 20 °C 3: triethylamine; tetrakis(triphenylphosphine) palladium(0) / toluene / 48 h / |Inert atmosphere; |Reflux View Scheme