pyridinium p-toluenesulfonate in methanol 4 h; Ambient temperature;

1: 93 percent / H2 / Lindlar's catalyst / hexane; ethanol 2: 73 percent / TEA / CH2Cl2 / 4 h / 0 °C 3: 1.) Mg, 2.) Li2CuCl3 / 1.) THF, 2.) 0 deg C, 3 h 4: 88 percent / PTS / methanol / 4 h / Ambient temperature View Scheme

1: 90 percent / potassium carbonate / tetrahydrofuran; diethyl ether / 25 h / 25 °C 2: 1.) n-BuLi, 2.) HMPA / 1.) THF, hexane, -30 deg C, 1 h, 2.) THF, hexane, -30 deg C, 1 h View Scheme

N,N,N',N',N'',N''-hexamethylphosphoric triamide; n-butyllithium 1.) THF, hexane, -30 deg C, 1 h, 2.) THF, hexane, -30 deg C, 1 h; Yield given. Multistep reaction;