1.1: dihydrogen peroxide; acetic acid / dichloromethane / 20 °C / Inert atmosphere 2.1: 2,2'-azo-bisisobutyronitrile; tri-n-butyl-tin hydride / toluene / 80 °C / Inert atmosphere 3.1: dimethyl sulfoxide; trifluoroacetic anhydride / dichloromethane / 0.83 h / -60 °C / Inert atmosphere 3.2: 1.5 h / -60 - 20 °C / Inert atmosphere 3.3: 20 °C / Inert atmosphere View Scheme

1: dihydrogen peroxide; acetic acid / dichloromethane / 20 °C / Inert atmosphere 2: 2,2'-azo-bisisobutyronitrile; tri-n-butyl-tin hydride / toluene / 80 °C / Inert atmosphere View Scheme