1.) ethanol, irrad., 0 deg C, 20 min, 2.) ethanol, reflux, 1.5 h; Yield given. Multistep reaction;

Multi-step reaction with 10 steps 1.1: 1H-imidazole / N,N-dimethyl-formamide / 6 h / 20 - 125 °C / |Large scale2.1: potassium tert-butylate / tetrahydrofuran / 4 h / 25 - 30 °C / |Large scale3.1: tetrahydrofuran / 4 h / 20 - 45 °C / |Large scale4.1: sodium hydroxide; dihydrogen peroxide / 1 h / 25 °C / |Large scale5.1: sodium hydride; 15-crown-5 / tetrahydrofuran; mineral oil / 6 h / 0 °C / |Large scale6.1: cerium(III) chloride / tetrahydrofuran / 0.5 h / -15 °C6.2: 0.5 h / -15 °C7.1: cerium(III) chloride / tetrahydrofuran / 0.5 h / -15 °C / |Large scale7.2: 0.5 h / -15 °C / |Large scale8.1: N-bromosuccinmide; 2,2'-azo-bisisobutyronitrile / n-heptane / 0.25 h / 78 °C9.1: 2,4,6-trimethyl-pyridine / toluene / 2.5 h / 110 °C / |Large scale10.1: tetrabutyl ammonium fluoride / tetrahydrofuran / 9 h / 66 °C  

Multi-step reaction with 8 steps 1.1: potassium tert-butylate / tetrahydrofuran / 4 h / 25 - 30 °C / |Large scale2.1: tetrahydrofuran / 4 h / 20 - 45 °C / |Large scale3.1: sodium hydroxide; dihydrogen peroxide / 1 h / 25 °C / |Large scale4.1: sodium hydride / tetrahydrofuran; mineral oil / 20 °C / |Large scale4.2: 1 h / 20 °C / |Reflux; |Large scale5.1: L-Selectridereg; / tetrahydrofuran / 1 h / |Reflux; |Large scale6.1: N-bromosuccinmide; 2,2'-azo-bisisobutyronitrile / n-heptane / 0.25 h / 78 °C7.1: 2,4,6-trimethyl-pyridine / toluene / 2.5 h / 110 °C / |Large scale8.1: tetrabutyl ammonium fluoride / tetrahydrofuran / 9 h / 66 °C