1: N-chloro-succinimide / acetone / 0 - 50 °C 2: sodium hydrogencarbonate; sodium hypochlorite; tetrabutylammomium bromide; potassium bromide; 2,2,6,6-tetramethyl-1-piperidinyloxy, free radical / hexane / -10 - 20 °C 3: potassium carbonate / N,N-dimethyl-formamide / 20 - 30 °C View Scheme