1: diethyl ether / 0.5 h / Ambient temperature 2: 79 percent / PCC, Celite / CH2Cl2 / Ambient temperature View Scheme

1.1: copper(l) iodide / tetrahydrofuran / 0.5 h / -78 °C 1.2: 2 h / -78 - -50 °C 2.1: boron trifluoride diethyl etherate / acetic anhydride / 20 °C / |Cooling with ice 3.1: sodium hydride; methanol / mineral oil / 0.5 h / 20 °C 4.1: potassium tert-butylate / tetrahydrofuran / 0.17 h / 0 °C 4.2: 1 h / |Reflux 5.1: potassium hydroxide / propan-1-ol / 1 h / 20 °C / |Reflux 6.1: ethyl acetate; diethyl ether / 0.08 h / 0 °C 7.1: lithium diisopropyl amide / tetrahydrofuran / -78 °C 7.2: 0.5 h / -78 °C 8.1: sodium hydrogencarbonate / para-xylene / 12 h / |Reflux 9.1: lithium aluminium tetrahydride / tetrahydrofuran / 0.5 h / 0 °C 10.1: triethylamine; 4-(N,N-dimethlyamino)pyridine / dichloromethane / 17 h / |Reflux 11.1: sodium tetrahydroborate / N,N-dimethyl-formamide / 12 h / 80 °C / |Cooling with ice 12.1: thiophenol; potassium carbonate / 1-methyl-pyrrolidin-2-one / 13 h / 220 °C View Scheme