1.1: N-iodo-succinimide / dichloromethane / 3.5 h / 10 - 20 °C 2.1: methanesulfonic acid / dichloromethane; tetrahydrofuran / 3.5 h / 10 - 20 °C 2.2: 10 °C 3.1: tributyl-amine / bis-triphenylphosphine-palladium(II) chloride / N,N-dimethyl-formamide / 18.67 h / 95 - 100 °C / Inert atmosphere 3.2: 3.67 h / 40 - 95 °C / Inert atmosphere 4.1: caesium carbonate / acetonitrile / 60 °C / Inert atmosphere 5.1: acetyl chloride; methanol / 4 h / 20 °C / Inert atmosphere; Cooling with ice 5.2: 0.5 h / 20 °C View Scheme