1: 90 percent / phosphorus pentaoxide, phosphoric acid / chlorobenzene / 1 h / 125 - 130 °C 2: 48 percent / benzoyl peroxide, N-bromosuccinimide / CCl4 / 8 h / Heating; Irradiation 3: 70 percent / 1.) hexamethylenetetramine / 1.) CHCl3, reflux, 4 h; 2.) H2O, AcOH, reflux, 3 h 4: 77 percent / silver oxide / H2O / icebath View Scheme

1: 90 percent / phosphorus pentaoxide, phosphoric acid / chlorobenzene / 1 h / 125 - 130 °C 2: 48 percent / benzoyl peroxide, N-bromosuccinimide / CCl4 / 8 h / Heating; Irradiation 3: 70 percent / 1.) hexamethylenetetramine / 1.) CHCl3, reflux, 4 h; 2.) H2O, AcOH, reflux, 3 h View Scheme

P2O5; phosphoric acid in chlorobenzene T=125 - 130°C; 1 h;

toluene-4-sulfonic acid in methanol T=50°C;

sodium ethanolate 20 h; Heating;

1: 1.) O3, 2.) Me2S / 1.) CH2Cl2, MeOH, -40 deg C, 2.) -40 deg C to room temp. 2: 75 percent / p-TsOH / methanol / 50 °C View Scheme