potassium hydroxide in methanol T=65 - 75°C;

1: With sodium tetrahydroborate; dibutyl ditelluride in tetrahydrofuran; methanol Substitution; 2: With toluene-4-sulfonic acid in benzene Dehydration; 0.5 h; Heating;

1: 80 percent / PdCl2(PPh3)2, CuI, piperidine / benzene / 12.5 h / 80 - 90 °C 2: 1.) tert-BuLi, 2.) Te / 1) ether, pentane, -80 deg C, 1 h, -80 to -30 deg C, 1 h; 2) ether, pentane, rt, 1-2 h 3: 74 percent / NaBH4 / ethanol / 12 h / 80 °C View Scheme

1: 1.) tert-BuLi, 2.) Te / 1) ether, pentane, -80 deg C, 1 h, -80 to -30 deg C, 1 h; 2) ether, pentane, rt, 1-2 h 2: 74 percent / NaBH4 / ethanol / 12 h / 80 °C View Scheme

1: 1.) BuLi, 2.) Te / 1.) ether, hexane, RT, 2 h, 2.) ether, hexane, RT, 20 h 2: 92 percent / TBAF / tetrahydrofuran / 2 h / Heating View Scheme

1: 1.) DIBAL-H, 2.) NBS / 1.) hexane, RT, 10 h, 2.) 0 deg C 2: 1.) BuLi, 2.) Te / 1.) ether, hexane, RT, 2 h, 2.) ether, hexane, RT, 20 h 3: 92 percent / TBAF / tetrahydrofuran / 2 h / Heating View Scheme

1: 1.) BuLi / 1.) ether, hexane, -78 deg C, 1.5 h, 2.) ether, hexane, a) -78 deg C, 1.5 h, b) RT, 10 h 2: 1.) DIBAL-H, 2.) NBS / 1.) hexane, RT, 10 h, 2.) 0 deg C 3: 1.) BuLi, 2.) Te / 1.) ether, hexane, RT, 2 h, 2.) ether, hexane, RT, 20 h 4: 92 percent / TBAF / tetrahydrofuran / 2 h / Heating View Scheme

1: 1.) BuLi, 2.) Te / 1.) ether, hexane, RT, 2 h, 2.) ether, hexane, RT, 20 h 2: 92 percent / TBAF / tetrahydrofuran / 2 h / Heating View Scheme