carbon tetrabromide; triphenylphosphine in tetrahydrofuran T=20°C; 0.5 h;

N-bromosuccinmide; meta-chloroperoxybenzoic acid in tetrachloromethane Heating;

1: sodium tetrahydroborate / 1,4-dioxane; methanol / 1 h / 0 - 20 °C 2: carbon tetrabromide; triphenylphosphine / tetrahydrofuran / 0.5 h / 20 °C View Scheme