1: N-allylbenzamide With ozone in dichloromethane T=-78°C; ozonolysis; 2: 1,1-dibromomethane With diethylamine in dichloromethane T=-78 - 55°C; Ring cleavage; methylenation;

oxalyl dichloride; dimethyl sulfoxide; triethylamine 1.) CH2Cl2, -70 deg C, 20 min, 2.) CH2Cl2, - 70 deg C, 20 min; Yield given. Multistep reaction;

1: 74 percent / aq. K2CO3 / 1.5 h / 5 °C 2: 1.) DMSO, oxalyl chloride, 2.) Et3N / 1.) CH2Cl2, -70 deg C, 20 min, 2.) CH2Cl2, - 70 deg C, 20 min View Scheme

ozone; diethylamine 1) -78 deg C, 2) - 78 deg C, 0.5 h; Yield given. Multistep reaction;