Hydrobromination of alkenes with PBr3/SiO2: a simple and efficient regiospecific preparation of alkyl bromides

Abstract

The reaction of several alkenes with 0.4 mol equiv. PBr3/SiO2 in dichloromethane at room temperature gave the alkyl bromides with Markovnikov regiospecificity in 50 - 100% yield and short reaction time. Isoprene at - 8 °C in these conditions gave 1-bromo-3-methyl-2-butene only (54%).

Keywords

• alkenes
• bromides
• electrophilic addition
• regiospecificity
• silica