Studies on Acetylenic Compounds. XXXIX. The Addition Reaction of Cyanogen Bromide to Acetylenic Compounds

The addition of cyanogen bromide to an acetylenic bond was studied. Phenylacetylene reacted with cyanogen bromide in the presence of aluminum bromide to afford trans-β-bromocinnamonitrile. Similarly, p-bromo-and p-methoxyphenylacetylene, tolane and methylphenylacetylene yielded corresponding β-bromocinnamonitriles. Nevertheless, p-nitrophenylacetylene did not react with cyanogen bromide under the same conditions.