sodium hexamethyldisilazane 1.) THF, HMPA, RT, 2 h, 2.) from -100 to 0 deg C, 4 h; Multistep reaction;

1: 1.) NaN(SiMe3)2 / 1.) THF, HMPA, RT, 2 h, 2.) from -100 to 0 deg C, 4 h 2: diethyl ether / 0 °C View Scheme

1: 80 percent / PPh3 / CH2Cl2 / 1 h / 0 °C 2: 91 percent / n-BuLi / hexane; tetrahydrofuran / 1.5 h / -78 - 0 °C 3: 1.) EtMgBr, 2.) CuBr / 1.) THF, reflux, 10 min, 2.) THF, reflux, 12 h 4: 65 percent / H2 / P-2 nickel / ethanol / 5 h 5: 76 percent / CBr4, PPh3 / CH2Cl2 / 10 h / Ambient temperature View Scheme