1.1: N-ethyl-N,N-diisopropylamine; methyl chloroformate / tetrahydrofuran / 0.75 h / 62 °C 1.2: 13 h / 0 - 20 °C 2.1: thionyl chloride / N,N-dimethyl-formamide / 5 h / 10 - 20 °C 3.1: sodium hexamethyldisilazane / N,N-dimethyl-formamide / -15 - 12 °C View Scheme

1.1: N-ethyl-N,N-diisopropylamine / tetrahydrofuran / 0.75 h / 20 - 62 °C / Inert atmosphere; Large scale reaction 2.1: sodium tetrahydroborate / tetrahydrofuran; water / 17.92 h / 0 - 22 °C / Inert atmosphere; Large scale reaction 2.2: 0 - 20 °C / Inert atmosphere; Large scale reaction View Scheme