1: 83 percent / imidazole / dimethylformamide / 18 h / 55 °C 2: CF3COOH, H2O / tetrahydrofuran / 1.5 h / Ambient temperature 3: tetrahydrofuran / 0.75 h / -78 °C 5: 90 percent / imidazole / dimethylformamide / 3 h / 55 °C 6: 1.) (dba)3Pd2*CHCl3, TPP, Et3N, 2.) TBAF / 1.) toluene, reflux, 2 h, 2.) THF, RT, 30 h View Scheme