1: 46 percent / LiBr, Li2CO3 / dimethylformamide / 1.) room temp., 10 min; 2.) 125 deg C, 2h 2: 85 percent / potassium tert-butoxide / hexamethylphosphoric acid triamide / 1.) -10 deg C, 25 min; 2.) room temp., 20 min View Scheme

1: 46 percent / LiBr, Li2CO3 / dimethylformamide / 1.) room temp., 10 min; 2.) 125 deg C, 2h 2: 27 percent / potassium tert-butoxide / hexamethylphosphoric acid triamide / 0.17 h / -8 - -3 °C View Scheme