thionyl chloride in pyridine Ambient temperature;

1.1: n-butyllithium / -70 - 20 °C 1.2: 6 h / 40 °C / |Inert atmosphere 2.1: 2,2,2-tribromo-2,2-dihydrobenzo-1,3,2-dioxaphosphole / dichloromethane / 47 °C / |Inert atmosphere View Scheme

1: acetic anhydride; dihydrogen peroxide / acetic acid / 20 °C 2: n-butyllithium / hexane; tetrahydrofuran / 3.5 h / -50 - 20 °C / |Inert atmosphere 3: |Acidic conditions 4: 2,2,2-tribromo-2,2-dihydrobenzo-1,3,2-dioxaphosphole / dichloromethane / 47 °C / |Inert atmosphere View Scheme

1: 1.) Bromine, Mg / 1.) Ether, 2.) THF, 15 h, reflux 2: 100 percent / Azoisobutyronitrile, N-Bromosuccinimide / CCl4 / 0.5 h / Heating 3: 71 percent / SOCl2 / pyridine / Ambient temperature View Scheme

1: 100 percent / Azoisobutyronitrile, N-Bromosuccinimide / CCl4 / 0.5 h / Heating 2: 71 percent / SOCl2 / pyridine / Ambient temperature View Scheme

1: 1.) Bromine, Mg / 1.) Ether, 2.) THF, 15 h, reflux 2: 100 percent / Azoisobutyronitrile, N-Bromosuccinimide / CCl4 / 0.5 h / Heating 3: 71 percent / SOCl2 / pyridine / Ambient temperature View Scheme