Rates of Bromination of Dimethyl Fumarate and of Dimethyl Acetylenedicarboxylate

Article abstract of DOI:10.1021/jo00207a029

Rates of bromination of dimethyl fumarate and of dimethyl acetylenedicarboxylate were determined in 50percent aqueous acetic acid in the presence of varying amounts of sodium bromide.In the presence of bromide ions both substrates are believed to react by the termolecular Ad_E3 mechanism, and the acetylenic substrate reacts faster than the olefin.The acetylene also reacts faster in the reaction which involves a bimolecular attack by bromine (Ad_E2).Usually olefins react considerably faster than acetylenes in halogenation, and possible reasons for the reversal of the relative rates observed here are discussed.