Abstract The cis and trans isomers of solid 1, 2-dibenzoylethylene, 1, 2-di-p- chlorobenzoylethylene and 1, 2-di-p-methyl-benzoylethylene yield, on exposure to bromine vapour at room temperature, the trans-adducts in quantitative yield except in the case of cis- 1, 2-di-p-methyl-benzoylethylene where isomerisation takes place prior to or during the bromination process yielding the same dibromide as the trans-isomer. The cis-trans ...
