1: With 4-(N,N-dimethlyamino)pyridine; anhydrous iron chloride; di-tert-butyl peroxide in 1,2-dichloro-ethane T=60°C; 18 h; Inert atmosphere; 2: With di-tert-butyl dicarbonate in 1,2-dichloro-ethane T=20°C; 1 h;