1: With potassium tert-butylate in tetrahydrofuran T=20°C; 2 h; 2: With sulfuric acid in tetrahydrofuran T=20°C; Further stages.;

1: (methoxymethyl)-triphenylphosphonium chloride With potassium tert-butylate in tetrahydrofuran T=0°C; 1 h; Inert atmosphere; 2: 2,2-dimethylpent-4-enal in tetrahydrofuran T=0 - 20°C; 2.5 h; 3: With sulfuric acid in tetrahydrofuran; water T=0 - 20°C; Inert atmosphere;

sulfuric acid in tetrahydrofuran 1 h;

1.1: dimethyl sulfoxide; triethylamine; sulfur trioxide pyridine complex / dichloromethane / 0 °C 2.1: potassium tert-butylate / tetrahydrofuran / 1 h / 0 °C 2.2: 2 h / 20 °C View Scheme

pyridinium chlorochromate

1: 91 percent / lithium aluminium hydride / diethyl ether / 4 h / Ambient temperature 2: 54 percent / N-bromosuccinimide, triphenylphosphine / benzene / 4 h View Scheme

diethylamine in methanol 2 h; Ambient temperature;

1: 91 percent / lithium aluminium hydride / diethyl ether / 4 h / Ambient temperature 2: 54 percent / N-bromosuccinimide, triphenylphosphine / benzene / 4 h 3: 1.) Mg, iodine / 1.) THF, 0.5 h, reflux; 2.) THF, -30 deg C to RT, RT, 1 h 4: 86 percent / cc. HCl / 12 h / Heating 5: 98 percent / potassium t-butoxide / diethyl ether / 0.5 h / 0 °C View Scheme