in N,N-dimethyl-formamide T=190°C; Claisen rearrangement; 12 h;

1: 63 percent / dimethylformamide / 12 h / 190 °C 2: 90 percent / potassium tert-butoxide / tetrahydrofuran / 24 h / Heating 3: 83 percent / triethylamine / CH2Cl2 / 3 h / 20 °C 4: 72 percent / Grubbs' second generation catalyst / CH2Cl2 / 24 h / Heating View Scheme