1: 1.) n-BuLi / 1.) hexane, THF, -10 deg C, 30 min, 2.) hexane, THF, HMPA, -10 deg C, 3 h 2: 57 percent / p-toluenesulfonic acid / methanol / 4 h / 60 °C 3: 91 percent / H2, quinoline / Pd/CaCO3 / hexane 4: 82 percent / pyridine / CH2Cl2 / 5 h / Ambient temperature View Scheme

1: 1.) n-BuLi / 1.) hexane, THF, -10 deg C, 30 min, 2.) hexane, THF, HMPA, -10 deg C, 3 h 2: 57 percent / p-toluenesulfonic acid / methanol / 4 h / 60 °C View Scheme

N,N,N',N',N'',N''-hexamethylphosphoric triamide; n-butyllithium 1.) THF, hexane, -20 deg C, 1 h, 2.) RT, 4 h; Multistep reaction;

1: 1.) n-BuLi / 1.) hexane, THF, -10 deg C, 30 min, 2.) hexane, THF, HMPA, -10 deg C, 3 h 2: 57 percent / p-toluenesulfonic acid / methanol / 4 h / 60 °C 3: 58 percent / LAH / bis-(2-methoxy-ethyl) ether / 48 h / Heating 4: 81 percent / pyridine / CH2Cl2 / 5 h / Ambient temperature View Scheme