1: 82 percent / 48percent HBr / methanol / 50 h / Heating 2: 82 percent / N-bromosuccinimide / methanol / 5 h / Ambient temperature 3: 62 percent / 18-crown-6 / acetonitrile / 120 h / Heating View Scheme

1: tetrahydrofuran / 0.5 h / -25 °C View Scheme

Yield given. Multistep reaction;

hydrogen bromide in methanol 50 h; Heating;