The reactions of acetylenes with bromine in alcohols at 20–25° C afford dibromodialkoxyalkanes in good yields together with variable amounts of dibromoalkenes. Similar treatment of phenylacetylene with copper (II) bromide gives only bromophenylacetylene and 2-phenyl-1, 1, 2-tribromoethylene, the latter being formed by dibromination of the former with copper (II) bromide.
