1: POCl3 / 0.5 h 2: dimethylformamide / 3 h / 80 °C 3: 72 percent / Mg / Li2CuCl4 / tetrahydrofuran / 10 min, -78 deg C then 2 h, 0 deg C then 15 h, r.t. 5: KOH / methanol; hexane; H2O / 2 h / Ambient temperature View Scheme

phosphorus tribromide in diethyl ether T=-20 - 20°C; 1.5 h;

1: POCl3 / 0.5 h 2: dimethylformamide / 3 h / 80 °C 3: 72 percent / Mg / Li2CuCl4 / tetrahydrofuran / 10 min, -78 deg C then 2 h, 0 deg C then 15 h, r.t. 4: 94 percent / pyridinium-p-toluolsulfonate / ethanol / 1.5 h / 55 °C View Scheme

potassium carbonate in methanol T=25°C; 2 h;

1: t-BuOCl / 1 h / 0 °C 2: 14.8 g / CuSO4; H2SO4 / acetic acid / 96 h / 20 °C 3: 75 percent / Na2CO3; H2O / methanol / 5 h / 0 °C View Scheme

1.1: N-bromosuccinimide; water / acetone / 15 h / 20 °C 1.2: 7.36 g / NaH / dimethylformamide / 15 h / 0 - 20 °C 2.1: 79 percent / NaIO4 / H2O; 2-methyl-propan-2-ol / 15 h / 20 °C 3.1: t-BuOCl / 1 h / 0 °C 4.1: 14.8 g / CuSO4; H2SO4 / acetic acid / 96 h / 20 °C 5.1: 75 percent / Na2CO3; H2O / methanol / 5 h / 0 °C View Scheme

1.1: POCl3 2.1: n-BuLi 2.2: -78 °C 3.1: TsOH / methanol 4.1: LiBHEt3; Pd(dppp)Cl2 / tetrahydrofuran 5.1: 81 percent / N-chlorosuccinimide; Me2S / CH2Cl2 / 1.5 h / 0 °C 6.1: dimethylformamide 7.1: 79 percent / n-BuLi 8.1: LiBHEt3; Pd(dppp)Cl2 / tetrahydrofuran 9.1: TBAF / tetrahydrofuran 10.1: Cp2ZrCl2 / 1,2-dichloro-ethane; hexane 10.2: 89 percent / NiCl2(PPh3)2; n-BuLi / tetrahydrofuran; hexane View Scheme

1: POCl3 / 0.5 h 2: dimethylformamide / 3 h / 80 °C 3: 72 percent / Mg / Li2CuCl4 / tetrahydrofuran / 10 min, -78 deg C then 2 h, 0 deg C then 15 h, r.t. View Scheme

1: 3-bromo-2-methylprop-1-ene With iodine; magnesium in tetrahydrofuran T=20°C; 1 h; 2: (E)-4-chloro-3-methyl-2-buten-1-ol With copper(l) iodide in tetrahydrofuran; diethyl ether T=-50°C; 3 h;

copper(l) iodide; magnesium 1.) THF, 2.) ether, -50 deg C, 3.) -50 to 25 deg C; Yield given. Multistep reaction;