hydrogenchloride; potassium hydroxide in methanol; water

1.1: n-butyllithium; diisopropylamine / tetrahydrofuran; hexane / 0.5 h / -78 °C / |Inert atmosphere 1.2: 7 h / -78 - 20 °C / |Inert atmosphere 2.1: lithium hydroxide hydrate / tetrahydrofuran; water / 17 h / 20 - 66 °C / |Inert atmosphere 2.2: 20 °C / pH 3 - 4 / |Inert atmosphere 3.1: oxalyl dichloride; N,N-dimethyl-formamide / dichloromethane / 1 h / 20 °C / |Inert atmosphere 4.1: tin(IV) chloride / dichloromethane / 22 h / |Reflux; |Inert atmosphere View Scheme