bis(trimethylsilyl)sulphate; tri-n-butyltin fluoride in tetrahydrofuran T=25°C; 1 h; other catalyst investigated; Product distribution;

ozone 1.) dichloromethane, -78 deg C, 0.5 h, 2.) carbon tetrachloride, reflux, 10 min; Yield given. Multistep reaction. Yields of byproduct given;

(i) NBS, (irradiation), (ii) Et3N; Multistep reaction;