N-ethyl-N,N-diisopropylamine in dichloromethane T=20°C; 15 h;

1: 90 percent / BF3*Et2O / CH2Cl2 / 5 h / 20 °C 2: 85 percent / (i-Pr)2NEt / CH2Cl2 / 15 h / 20 °C View Scheme

1: 2-(4-methoxymethoxy-butyl)-[1,3]dithiane With n-butyllithium in tetrahydrofuran T=-25°C; 4 h; 2: (E)-1-Iodo-non-4-ene With N,N,N',N',N'',N''-hexamethylphosphoric triamide in tetrahydrofuran T=0°C; 17 h;

1.1: n-BuLi / tetrahydrofuran / 4 h / -25 °C 1.2: 68 percent / HMPA / tetrahydrofuran / 17 h / 0 °C 2.1: 90 percent / p-TsOH*H2O / tetrahydrofuran / 3 h / 40 °C View Scheme

1.1: n-BuLi / tetrahydrofuran / 4 h / -25 °C 1.2: 68 percent / HMPA / tetrahydrofuran / 17 h / 0 °C 2.1: 90 percent / p-TsOH*H2O / tetrahydrofuran / 3 h / 40 °C 3.1: 86 percent / SO3*pyridine / dimethylsulfoxide; CH2Cl2 / 0.5 h / cooling View Scheme