Isomer ratios from the bromination of allyl chloride in water, methanol, acetic acid, and trifluoroacetic acid

Abstract

In a hydroxylic solvent HOR (water, methanol, acetic acid, or trifluoroacetic acid), bromine reacts with allyl chloride to yield 1,2-dibromo-3-chloropropane together with the 1-bromo-2-OR and 2-bromo-1-OR products. As expected the yield of the dibromide increases as the nucleophilicity of the solvent is decreased, but the ratio of the other two isomeric products remains approximately constant at 30 : 70 over the range of solvents studied. The results, together with those obtained by other workers for similar electrophilic additions, are discussed in terms of the structures of the intermediate carbocations.