1: methyl phenyl sulphoxide With trifluoroacetic anhydride in dichloromethane T=-78°C; 0.25 h; 2: 1,2-dihydrofuran in dichloromethane T=-78°C; 0.25 h; 3: With triethylamine in dichloromethane T=-78 - 20°C; Further stages.;

potassium tert-butylate in tetrahydrofuran T=-70 - 20°C; 1 h;

1: N-chlorosuccinimide / CH2Cl2 / 0.5 h / 0 °C 2: 71 percent / KOBu-t / tetrahydrofuran / 1 h / -70 - 20 °C View Scheme

1: CH2Cl2 / 0.25 h / -78 °C 2: CH2Cl2 / 0.25 h / -78 °C 3: Et3N / CH2Cl2 / 24 h / Ambient temperature View Scheme

1: CH2Cl2 / 0.25 h / -78 °C 2: Et3N / CH2Cl2 / 24 h / Ambient temperature View Scheme