1: 67 percent / LDA / hexamethylphosphoric acid triamide / 2 h / -78 °C 2: 1.) BH2Cl*SMe2, 2.) H2O, 3.) PCC / 1) CH2Cl2, rt, 2 h; 2) CH2Cl2, reflux, 0.5 h; 3) CH2Cl2, reflux, 3 h 3: 1.) TiCl4, Ti(OPr-i)4 / 1) Et2O, rt, 1 h; 2) Et2O, 0 deg C --> rt 4: 99 percent / LiOH / H2O; tetrahydrofuran / Ambient temperature 5: Ph3P, diethyl azodicarboxylate / toluene / 9 h View Scheme