1.1: sodium tetrahydroborate / methanol / 0.5 h / Cooling with ice 2.1: 1H-imidazole / N,N-dimethyl-formamide / 10.25 h / 0 - 20 °C / Inert atmosphere 3.1: N-bromosuccinmide; dihydrogen peroxide / tetrachloromethane / 4 h / Reflux 4.1: magnesium / tetrahydrofuran / 2 h / Inert atmosphere 4.2: 4 h / Inert atmosphere 4.3: 4 h / Inert atmosphere 5.1: tetrabutyl ammonium fluoride / tetrahydrofuran / 4 h / Inert atmosphere View Scheme